Merge branch 'develop'

.github/workflows/main.yml

@@ -1,4 +1,4 @@
-name: Release an APK and an App Bundle on tagging
+name: Release on tag
 
 on:
   push:
@@ -33,9 +33,11 @@ jobs:
         working-directory: ${{ github.workspace }}/scripts
         run: ./update_flutter_version.sh
 
-      # `flutter test` fails if test directory is missing
-      #- name: Run the unit tests.
-      #  run: flutter test
+      - name: Static analysis.
+        run: flutter analyze
+
+      - name: Unit tests.
+        run: flutter test
 
       - name: Build signed artifacts.
         # `KEY_JKS` should contain the result of:

README.md

@@ -1,7 +1,15 @@
-![Aves logo][] [<img src="https://play.google.com/intl/en_us/badges/static/images/badges/en_badge_web_generic.png" alt='Get it on Google Play' width="200">](https://play.google.com/store/apps/details?id=deckers.thibault.aves&pcampaignid=pcampaignidMKT-Other-global-all-co-prtnr-py-PartBadge-Mar2515-1)
+![Version badge][Version badge]
+![Build badge][Build badge]
+
+<br />
+<img src="https://raw.githubusercontent.com/deckerst/aves/develop/assets/aves_logo.svg" alt='Aves logo' width="200" />
+
+[<img src="https://play.google.com/intl/en_us/badges/static/images/badges/en_badge_web_generic.png" alt='Get it on Google Play' width="200">](https://play.google.com/store/apps/details?id=deckers.thibault.aves&pcampaignid=pcampaignidMKT-Other-global-all-co-prtnr-py-PartBadge-Mar2515-1)
 
 Aves is a gallery and metadata explorer app. It is built for Android, with Flutter.
 
+<img src="https://raw.githubusercontent.com/deckerst/aves/develop/extra/play/screenshots%20v1.0.0/S10/1-S10-collection.jpg" alt='Collection screenshot' height="400" /><img src="https://raw.githubusercontent.com/deckerst/aves/develop/extra/play/screenshots%20v1.0.0/S10/2-S10-image.jpg" alt='Image screenshot' height="400" /><img src="https://raw.githubusercontent.com/deckerst/aves/develop/extra/play/screenshots%20v1.0.0/S10/5-S10-stats.jpg" alt='Stats screenshot' height="400" />
+
 ## Features
 
 - support raster images: JPEG, PNG, GIF, WEBP, BMP, WBMP, HEIC (from Android Pie)
@@ -13,7 +21,7 @@ Aves is a gallery and metadata explorer app. It is built for Android, with Flutt
 - favorites
 - statistics
 - handle intents to view or pick images
-- support Android API 24 ~ 29 (Nougat ~ Android 10)
+- support Android API 24 ~ 30 (Nougat ~ R)
 
 ## Roadmap
 
@@ -25,7 +33,6 @@ If time permits, I intend to eventually add these:
 - gesture: long press and drag thumbnails to select multiple items
 - gesture: double tap and drag image to zoom in/out (aka quick scale, one finger zoom)
 - support: burst groups
-- support: Android R
 - subsampling/tiling
 
 ## Known Issues
@@ -48,4 +55,5 @@ If time permits, I intend to eventually add these:
 
 Create a file named `<app dir>/android/key.properties`. It should contain a reference to a keystore for app signing, and other necessary credentials. See `<app dir>/android/key_template.properties` for the expected keys.
 
-[Aves logo]: https://github.com/deckerst/aves/blob/master/android/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.png
+[Version badge]: https://img.shields.io/github/v/release/deckerst/aves?include_prereleases&sort=semver
+[Build badge]: https://img.shields.io/github/workflow/status/deckerst/aves/Release%20on%20tag

analysis_options.yaml

@@ -4,9 +4,30 @@ analyzer:
   exclude:
     - lib/generated_plugin_registrant.dart
 
+#  strong-mode:
+#    implicit-casts: false
+#    implicit-dynamic: false
+
 linter:
   rules:
-    - always_declare_return_types
-    - prefer_const_constructors
-    - prefer_const_constructors_in_immutables
-    - prefer_const_declarations
+    # from 'effective dart', excluded
+    avoid_function_literals_in_foreach_calls: false # benefit?
+    lines_longer_than_80_chars: false # nope
+    avoid_classes_with_only_static_members: false # too strict
+
+    # from 'effective dart', undecided
+    prefer_relative_imports: false # check IDE support (auto import, file move)
+    public_member_api_docs: false # maybe?
+
+    # from 'effective dart', included
+    avoid_types_on_closure_parameters: true
+    constant_identifier_names: true
+    prefer_function_declarations_over_variables: true
+    prefer_interpolation_to_compose_strings: true
+    unnecessary_brace_in_string_interps: true
+    unnecessary_lambdas: true
+
+    # misc
+    prefer_const_constructors: false # too noisy
+    prefer_const_constructors_in_immutables: true
+    prefer_const_declarations: true

android/app/build.gradle

@@ -41,7 +41,7 @@ if (keystorePropertiesFile.exists()) {
 }
 
 android {
-    compileSdkVersion 29 // latest (or latest-1 if the sources of latest SDK are unavailable)
+    compileSdkVersion 30 // latest (or latest-1 if the sources of latest SDK are unavailable)
 
     lintOptions {
         disable 'InvalidPackage'
@@ -54,7 +54,7 @@ android {
         // but Flutter (as of v1.17.3) fails to run in release mode when using Gradle plugin 4.0:
         // https://github.com/flutter/flutter/issues/58247
         minSdkVersion 24
-        targetSdkVersion 29 // same as compileSdkVersion
+        targetSdkVersion 30 // same as compileSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
         manifestPlaceholders = [googleApiKey:keystoreProperties['googleApiKey']]

android/app/src/main/AndroidManifest.xml

@@ -36,6 +36,14 @@
     -->
     <uses-permission android:name="android.permission.WAKE_LOCK" />
 
+    <!-- from Android R, we should define <queries> to make other apps visible to this app -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.MAIN" />
+            <category android:name="android.intent.category.LAUNCHER" />
+        </intent>
+    </queries>
+
     <application
         android:name="io.flutter.app.FlutterApplication"
         android:icon="@mipmap/ic_launcher"

android/app/src/main/java/deckers/thibault/aves/MainActivity.java

@@ -100,7 +100,7 @@ public class MainActivity extends FlutterActivity {
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         if (requestCode == PermissionManager.VOLUME_ROOT_PERMISSION_REQUEST_CODE) {
             if (resultCode != RESULT_OK || data.getData() == null) {
-                PermissionManager.onPermissionResult(this, requestCode, false, null);
+                PermissionManager.onPermissionResult(requestCode, null);
                 return;
             }
 
@@ -113,7 +113,7 @@ public class MainActivity extends FlutterActivity {
             getContentResolver().takePersistableUriPermission(treeUri, takeFlags);
 
             // resume pending action
-            PermissionManager.onPermissionResult(this, requestCode, true, treeUri);
+            PermissionManager.onPermissionResult(requestCode, treeUri);
         }
     }
 }

android/app/src/main/java/deckers/thibault/aves/channel/calls/StorageHandler.java

@@ -1,6 +1,6 @@
 package deckers.thibault.aves.channel.calls;
 
-import android.app.Activity;
+import android.content.Context;
 import android.os.Build;
 import android.os.storage.StorageManager;
 import android.os.storage.StorageVolume;
@@ -22,10 +22,10 @@ import io.flutter.plugin.common.MethodChannel;
 public class StorageHandler implements MethodChannel.MethodCallHandler {
     public static final String CHANNEL = "deckers.thibault/aves/storage";
 
-    private Activity activity;
+    private Context context;
 
-    public StorageHandler(Activity activity) {
-        this.activity = activity;
+    public StorageHandler(Context context) {
+        this.context = context;
     }
 
     @Override
@@ -42,12 +42,12 @@ public class StorageHandler implements MethodChannel.MethodCallHandler {
                 result.success(volumes);
                 break;
             }
-            case "requireVolumeAccessDialog": {
-                String path = call.argument("path");
-                if (path == null) {
-                    result.success(true);
+            case "getInaccessibleDirectories": {
+                List<String> dirPaths = call.argument("dirPaths");
+                if (dirPaths == null) {
+                    result.error("getInaccessibleDirectories-args", "failed because of missing arguments", null);
                 } else {
-                    result.success(PermissionManager.requireVolumeAccessDialog(activity, path));
+                    result.success(PermissionManager.getInaccessibleDirectories(context, dirPaths));
                 }
                 break;
             }
@@ -60,15 +60,15 @@ public class StorageHandler implements MethodChannel.MethodCallHandler {
     @RequiresApi(api = Build.VERSION_CODES.N)
     private List<Map<String, Object>> getStorageVolumes() {
         List<Map<String, Object>> volumes = new ArrayList<>();
-        StorageManager sm = activity.getSystemService(StorageManager.class);
+        StorageManager sm = context.getSystemService(StorageManager.class);
         if (sm != null) {
-            for (String volumePath : StorageUtils.getVolumePaths(activity)) {
+            for (String volumePath : StorageUtils.getVolumePaths(context)) {
                 try {
                     StorageVolume volume = sm.getStorageVolume(new File(volumePath));
                     if (volume != null) {
                         Map<String, Object> volumeMap = new HashMap<>();
                         volumeMap.put("path", volumePath);
-                        volumeMap.put("description", volume.getDescription(activity));
+                        volumeMap.put("description", volume.getDescription(context));
                         volumeMap.put("isPrimary", volume.isPrimary());
                         volumeMap.put("isRemovable", volume.isRemovable());
                         volumeMap.put("isEmulated", volume.isEmulated());

android/app/src/main/java/deckers/thibault/aves/channel/streams/ImageOpStreamHandler.java

@@ -1,6 +1,6 @@
 package deckers.thibault.aves.channel.streams;
 
-import android.app.Activity;
+import android.content.Context;
 import android.net.Uri;
 import android.os.Handler;
 import android.os.Looper;
@@ -25,7 +25,7 @@ public class ImageOpStreamHandler implements EventChannel.StreamHandler {
 
     public static final String CHANNEL = "deckers.thibault/aves/imageopstream";
 
-    private Activity activity;
+    private Context context;
     private EventChannel.EventSink eventSink;
     private Handler handler;
     private Map<String, Object> argMap;
@@ -33,8 +33,8 @@ public class ImageOpStreamHandler implements EventChannel.StreamHandler {
     private String op;
 
     @SuppressWarnings("unchecked")
-    public ImageOpStreamHandler(Activity activity, Object arguments) {
-        this.activity = activity;
+    public ImageOpStreamHandler(Context context, Object arguments) {
+        this.context = context;
         if (arguments instanceof Map) {
             argMap = (Map<String, Object>) arguments;
             this.op = (String) argMap.get("op");
@@ -100,7 +100,7 @@ public class ImageOpStreamHandler implements EventChannel.StreamHandler {
         }
 
         List<AvesImageEntry> entries = entryMapList.stream().map(AvesImageEntry::new).collect(Collectors.toList());
-        provider.moveMultiple(activity, copy, destinationDir, entries, new ImageProvider.ImageOpCallback() {
+        provider.moveMultiple(context, copy, destinationDir, entries, new ImageProvider.ImageOpCallback() {
             @Override
             public void onSuccess(Map<String, Object> fields) {
                 success(fields);
@@ -138,7 +138,7 @@ public class ImageOpStreamHandler implements EventChannel.StreamHandler {
                 put("uri", uriString);
             }};
             try {
-                provider.delete(activity, path, uri).get();
+                provider.delete(context, path, uri).get();
                 result.put("success", true);
             } catch (ExecutionException | InterruptedException e) {
                 Log.w(LOG_TAG, "failed to delete entry with path=" + path, e);

android/app/src/main/java/deckers/thibault/aves/channel/streams/MediaStoreStreamHandler.java

@@ -1,6 +1,6 @@
 package deckers.thibault.aves.channel.streams;
 
-import android.app.Activity;
+import android.content.Context;
 import android.os.Handler;
 import android.os.Looper;
 
@@ -12,14 +12,14 @@ import io.flutter.plugin.common.EventChannel;
 public class MediaStoreStreamHandler implements EventChannel.StreamHandler {
     public static final String CHANNEL = "deckers.thibault/aves/mediastorestream";
 
-    private Activity activity;
+    private Context context;
     private EventChannel.EventSink eventSink;
     private Handler handler;
     private Map<Integer, Integer> knownEntries;
 
     @SuppressWarnings("unchecked")
-    public MediaStoreStreamHandler(Activity activity, Object arguments) {
-        this.activity = activity;
+    public MediaStoreStreamHandler(Context context, Object arguments) {
+        this.context = context;
         if (arguments instanceof Map) {
             Map<String, Object> argMap = (Map<String, Object>) arguments;
             this.knownEntries = (Map<Integer, Integer>) argMap.get("knownEntries");
@@ -47,7 +47,7 @@ public class MediaStoreStreamHandler implements EventChannel.StreamHandler {
     }
 
     void fetchAll() {
-        new MediaStoreImageProvider().fetchAll(activity, knownEntries, this::success); // 350ms
+        new MediaStoreImageProvider().fetchAll(context, knownEntries, this::success); // 350ms
         endOfStream();
     }
 }

android/app/src/main/java/deckers/thibault/aves/channel/streams/StorageAccessStreamHandler.java

@@ -17,14 +17,14 @@ public class StorageAccessStreamHandler implements EventChannel.StreamHandler {
     private Activity activity;
     private EventChannel.EventSink eventSink;
     private Handler handler;
-    private String volumePath;
+    private String path;
 
     @SuppressWarnings("unchecked")
     public StorageAccessStreamHandler(Activity activity, Object arguments) {
         this.activity = activity;
         if (arguments instanceof Map) {
             Map<String, Object> argMap = (Map<String, Object>) arguments;
-            this.volumePath = (String) argMap.get("path");
+            this.path = (String) argMap.get("path");
         }
     }
 
@@ -32,9 +32,9 @@ public class StorageAccessStreamHandler implements EventChannel.StreamHandler {
     public void onListen(Object o, final EventChannel.EventSink eventSink) {
         this.eventSink = eventSink;
         this.handler = new Handler(Looper.getMainLooper());
-        Runnable onGranted = () -> success(!PermissionManager.requireVolumeAccessDialog(activity, volumePath));
-        Runnable onDenied = () -> success(false);
-        PermissionManager.requestVolumeAccess(activity, volumePath, onGranted, onDenied);
+        Runnable onGranted = () -> success(true); // user gave access to a directory, with no guarantee that it matches the specified `path`
+        Runnable onDenied = () -> success(false); // user cancelled
+        PermissionManager.requestVolumeAccess(activity, path, onGranted, onDenied);
     }
 
     @Override

android/app/src/main/java/deckers/thibault/aves/model/SourceImageEntry.java

@@ -8,6 +8,7 @@ import android.media.MediaMetadataRetriever;
 import android.net.Uri;
 import android.os.Build;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.drew.imaging.ImageMetadataReader;
@@ -53,7 +54,7 @@ public class SourceImageEntry {
     public SourceImageEntry() {
     }
 
-    public SourceImageEntry(Map<String, Object> map) {
+    public SourceImageEntry(@NonNull Map<String, Object> map) {
         this.uri = Uri.parse((String) map.get("uri"));
         this.path = (String) map.get("path");
         this.sourceMimeType = (String) map.get("sourceMimeType");
@@ -121,7 +122,7 @@ public class SourceImageEntry {
 
     // expects entry with: uri, mimeType
     // finds: width, height, orientation/rotation, date, title, duration
-    public SourceImageEntry fillPreCatalogMetadata(Context context) {
+    public SourceImageEntry fillPreCatalogMetadata(@NonNull Context context) {
         fillByMediaMetadataRetriever(context);
         if (hasSize() && (!isVideo() || hasDuration())) return this;
         fillByMetadataExtractor(context);
@@ -132,7 +133,7 @@ public class SourceImageEntry {
 
     // expects entry with: uri, mimeType
     // finds: width, height, orientation/rotation, date, title, duration
-    private void fillByMediaMetadataRetriever(Context context) {
+    private void fillByMediaMetadataRetriever(@NonNull Context context) {
         MediaMetadataRetriever retriever = StorageUtils.openMetadataRetriever(context, uri);
         try {
             String width = null, height = null, rotation = null, durationMillis = null;
@@ -182,7 +183,7 @@ public class SourceImageEntry {
 
     // expects entry with: uri, mimeType
     // finds: width, height, orientation, date
-    private void fillByMetadataExtractor(Context context) {
+    private void fillByMetadataExtractor(@NonNull Context context) {
         if (isSvg()) return;
 
         try (InputStream is = StorageUtils.openInputStream(context, uri)) {
@@ -244,7 +245,7 @@ public class SourceImageEntry {
 
     // expects entry with: uri
     // finds: width, height
-    private void fillByBitmapDecode(Context context) {
+    private void fillByBitmapDecode(@NonNull Context context) {
         if (isSvg()) return;
 
         try (InputStream is = StorageUtils.openInputStream(context, uri)) {
@@ -260,7 +261,7 @@ public class SourceImageEntry {
 
     // convenience method
 
-    private static Long toLong(Object o) {
+    private static Long toLong(@Nullable Object o) {
         if (o == null) return null;
         if (o instanceof Integer) return Long.valueOf((Integer) o);
         return (long) o;

android/app/src/main/java/deckers/thibault/aves/model/provider/ImageProvider.java

@@ -1,6 +1,5 @@
 package deckers.thibault.aves.model.provider;
 
-import android.app.Activity;
 import android.content.ContentUris;
 import android.content.Context;
 import android.database.Cursor;
@@ -9,8 +8,6 @@ import android.graphics.BitmapFactory;
 import android.graphics.Matrix;
 import android.media.MediaScannerConnection;
 import android.net.Uri;
-import android.os.Handler;
-import android.os.Looper;
 import android.provider.MediaStore;
 import android.util.Log;
 
@@ -32,7 +29,6 @@ import java.util.Map;
 import deckers.thibault.aves.model.AvesImageEntry;
 import deckers.thibault.aves.utils.MetadataHelper;
 import deckers.thibault.aves.utils.MimeTypes;
-import deckers.thibault.aves.utils.PermissionManager;
 import deckers.thibault.aves.utils.StorageUtils;
 import deckers.thibault.aves.utils.Utils;
 
@@ -52,15 +48,15 @@ public abstract class ImageProvider {
         callback.onFailure(new UnsupportedOperationException());
     }
 
-    public ListenableFuture<Object> delete(final Activity activity, final String path, final Uri uri) {
+    public ListenableFuture<Object> delete(final Context context, final String path, final Uri uri) {
         return Futures.immediateFailedFuture(new UnsupportedOperationException());
     }
 
-    public void moveMultiple(final Activity activity, final Boolean copy, final String destinationDir, final List<AvesImageEntry> entries, @NonNull final ImageOpCallback callback) {
+    public void moveMultiple(final Context context, final Boolean copy, final String destinationDir, final List<AvesImageEntry> entries, @NonNull final ImageOpCallback callback) {
         callback.onFailure(new UnsupportedOperationException());
     }
 
-    public void rename(final Activity activity, final String oldPath, final Uri oldMediaUri, final String mimeType, final String newFilename, final ImageOpCallback callback) {
+    public void rename(final Context context, final String oldPath, final Uri oldMediaUri, final String mimeType, final String newFilename, final ImageOpCallback callback) {
         if (oldPath == null) {
             callback.onFailure(new IllegalArgumentException("entry does not have a path, uri=" + oldMediaUri));
             return;
@@ -74,13 +70,7 @@ public abstract class ImageProvider {
             return;
         }
 
-        if (PermissionManager.requireVolumeAccessDialog(activity, oldPath)) {
-            Runnable runnable = () -> rename(activity, oldPath, oldMediaUri, mimeType, newFilename, callback);
-            new Handler(Looper.getMainLooper()).post(() -> PermissionManager.showVolumeAccessDialog(activity, oldPath, runnable));
-            return;
-        }
-
-        DocumentFileCompat df = StorageUtils.getDocumentFile(activity, oldPath, oldMediaUri);
+        DocumentFileCompat df = StorageUtils.getDocumentFile(context, oldPath, oldMediaUri);
         try {
             boolean renamed = df != null && df.renameTo(newFilename);
             if (!renamed) {
@@ -92,33 +82,27 @@ public abstract class ImageProvider {
             return;
         }
 
-        MediaScannerConnection.scanFile(activity, new String[]{oldPath}, new String[]{mimeType}, null);
-        scanNewPath(activity, newFile.getPath(), mimeType, callback);
-    }
-
-    public void rotate(final Activity activity, final String path, final Uri uri, final String mimeType, final boolean clockwise, final ImageOpCallback callback) {
-        if (PermissionManager.requireVolumeAccessDialog(activity, path)) {
-            Runnable runnable = () -> rotate(activity, path, uri, mimeType, clockwise, callback);
-            new Handler(Looper.getMainLooper()).post(() -> PermissionManager.showVolumeAccessDialog(activity, path, runnable));
-            return;
+        MediaScannerConnection.scanFile(context, new String[]{oldPath}, new String[]{mimeType}, null);
+        scanNewPath(context, newFile.getPath(), mimeType, callback);
     }
 
+    public void rotate(final Context context, final String path, final Uri uri, final String mimeType, final boolean clockwise, final ImageOpCallback callback) {
         switch (mimeType) {
             case MimeTypes.JPEG:
-                rotateJpeg(activity, path, uri, clockwise, callback);
+                rotateJpeg(context, path, uri, clockwise, callback);
                 break;
             case MimeTypes.PNG:
-                rotatePng(activity, path, uri, clockwise, callback);
+                rotatePng(context, path, uri, clockwise, callback);
                 break;
             default:
                 callback.onFailure(new UnsupportedOperationException("unsupported mimeType=" + mimeType));
         }
     }
 
-    private void rotateJpeg(final Activity activity, final String path, final Uri uri, boolean clockwise, final ImageOpCallback callback) {
+    private void rotateJpeg(final Context context, final String path, final Uri uri, boolean clockwise, final ImageOpCallback callback) {
         final String mimeType = MimeTypes.JPEG;
 
-        final DocumentFileCompat originalDocumentFile = StorageUtils.getDocumentFile(activity, path, uri);
+        final DocumentFileCompat originalDocumentFile = StorageUtils.getDocumentFile(context, path, uri);
         if (originalDocumentFile == null) {
             callback.onFailure(new Exception("failed to get document file for path=" + path + ", uri=" + uri));
             return;
@@ -163,7 +147,7 @@ public abstract class ImageProvider {
         Map<String, Object> newFields = new HashMap<>();
         newFields.put("orientationDegrees", orientationDegrees);
 
-//        ContentResolver contentResolver = activity.getContentResolver();
+//        ContentResolver contentResolver = context.getContentResolver();
 //        ContentValues values = new ContentValues();
 //        // from Android Q, media store update needs to be flagged IS_PENDING first
 //        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
@@ -178,17 +162,17 @@ public abstract class ImageProvider {
 //        // TODO TLAD catch RecoverableSecurityException
 //        int updatedRowCount = contentResolver.update(uri, values, null, null);
 //        if (updatedRowCount > 0) {
-        MediaScannerConnection.scanFile(activity, new String[]{path}, new String[]{mimeType}, (p, u) -> callback.onSuccess(newFields));
+        MediaScannerConnection.scanFile(context, new String[]{path}, new String[]{mimeType}, (p, u) -> callback.onSuccess(newFields));
 //        } else {
 //            Log.w(LOG_TAG, "failed to update fields in Media Store for uri=" + uri);
 //            callback.onSuccess(newFields);
 //        }
     }
 
-    private void rotatePng(final Activity activity, final String path, final Uri uri, boolean clockwise, final ImageOpCallback callback) {
+    private void rotatePng(final Context context, final String path, final Uri uri, boolean clockwise, final ImageOpCallback callback) {
         final String mimeType = MimeTypes.PNG;
 
-        final DocumentFileCompat originalDocumentFile = StorageUtils.getDocumentFile(activity, path, uri);
+        final DocumentFileCompat originalDocumentFile = StorageUtils.getDocumentFile(context, path, uri);
         if (originalDocumentFile == null) {
             callback.onFailure(new Exception("failed to get document file for path=" + path + ", uri=" + uri));
             return;
@@ -203,7 +187,7 @@ public abstract class ImageProvider {
 
         Bitmap originalImage;
         try {
-            originalImage = BitmapFactory.decodeStream(StorageUtils.openInputStream(activity, uri));
+            originalImage = BitmapFactory.decodeStream(StorageUtils.openInputStream(context, uri));
         } catch (FileNotFoundException e) {
             callback.onFailure(e);
             return;
@@ -235,7 +219,7 @@ public abstract class ImageProvider {
         newFields.put("width", rotatedWidth);
         newFields.put("height", rotatedHeight);
 
-//        ContentResolver contentResolver = activity.getContentResolver();
+//        ContentResolver contentResolver = context.getContentResolver();
 //        ContentValues values = new ContentValues();
 //        // from Android Q, media store update needs to be flagged IS_PENDING first
 //        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
@@ -250,15 +234,15 @@ public abstract class ImageProvider {
 //        // TODO TLAD catch RecoverableSecurityException
 //        int updatedRowCount = contentResolver.update(uri, values, null, null);
 //        if (updatedRowCount > 0) {
-        MediaScannerConnection.scanFile(activity, new String[]{path}, new String[]{mimeType}, (p, u) -> callback.onSuccess(newFields));
+        MediaScannerConnection.scanFile(context, new String[]{path}, new String[]{mimeType}, (p, u) -> callback.onSuccess(newFields));
 //        } else {
 //            Log.w(LOG_TAG, "failed to update fields in Media Store for uri=" + uri);
 //            callback.onSuccess(newFields);
 //        }
     }
 
-    protected void scanNewPath(final Activity activity, final String path, final String mimeType, final ImageOpCallback callback) {
-        MediaScannerConnection.scanFile(activity, new String[]{path}, new String[]{mimeType}, (newPath, newUri) -> {
+    protected void scanNewPath(final Context context, final String path, final String mimeType, final ImageOpCallback callback) {
+        MediaScannerConnection.scanFile(context, new String[]{path}, new String[]{mimeType}, (newPath, newUri) -> {
             Log.d(LOG_TAG, "scanNewPath onScanCompleted with newPath=" + newPath + ", newUri=" + newUri);
 
             long contentId = 0;
@@ -282,7 +266,7 @@ public abstract class ImageProvider {
             // we retrieve updated fields as the renamed file became a new entry in the Media Store
             String[] projection = {MediaStore.MediaColumns.TITLE};
             try {
-                Cursor cursor = activity.getContentResolver().query(contentUri, projection, null, null, null);
+                Cursor cursor = context.getContentResolver().query(contentUri, projection, null, null, null);
                 if (cursor != null) {
                     if (cursor.moveToNext()) {
                         newFields.put("uri", contentUri.toString());

android/app/src/main/java/deckers/thibault/aves/model/provider/MediaStoreImageProvider.java

@@ -1,15 +1,12 @@
 package deckers.thibault.aves.model.provider;
 
 import android.annotation.SuppressLint;
-import android.app.Activity;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Build;
-import android.os.Handler;
-import android.os.Looper;
 import android.os.storage.StorageManager;
 import android.os.storage.StorageVolume;
 import android.provider.MediaStore;
@@ -35,7 +32,6 @@ import java.util.stream.Stream;
 import deckers.thibault.aves.model.AvesImageEntry;
 import deckers.thibault.aves.model.SourceImageEntry;
 import deckers.thibault.aves.utils.MimeTypes;
-import deckers.thibault.aves.utils.PermissionManager;
 import deckers.thibault.aves.utils.StorageUtils;
 import deckers.thibault.aves.utils.Utils;
 
@@ -213,26 +209,14 @@ public class MediaStoreImageProvider extends ImageProvider {
     }
 
     @Override
-    public ListenableFuture<Object> delete(final Activity activity, final String path, final Uri mediaUri) {
+    public ListenableFuture<Object> delete(final Context context, final String path, final Uri mediaUri) {
         SettableFuture<Object> future = SettableFuture.create();
 
         if (StorageUtils.requireAccessPermission(path)) {
-            if (PermissionManager.getVolumeTreeUri(activity, path) == null) {
-                Runnable runnable = () -> {
-                    try {
-                        future.set(delete(activity, path, mediaUri).get());
-                    } catch (Exception e) {
-                        future.setException(e);
-                    }
-                };
-                new Handler(Looper.getMainLooper()).post(() -> PermissionManager.showVolumeAccessDialog(activity, path, runnable));
-                return future;
-            }
-
             // if the file is on SD card, calling the content resolver delete() removes the entry from the Media Store
             // but it doesn't delete the file, even if the app has the permission
             try {
-                DocumentFileCompat df = StorageUtils.getDocumentFile(activity, path, mediaUri);
+                DocumentFileCompat df = StorageUtils.getDocumentFile(context, path, mediaUri);
                 if (df != null && df.delete()) {
                     future.set(null);
                 } else {
@@ -245,7 +229,7 @@ public class MediaStoreImageProvider extends ImageProvider {
         }
 
         try {
-            if (activity.getContentResolver().delete(mediaUri, null, null) > 0) {
+            if (context.getContentResolver().delete(mediaUri, null, null) > 0) {
                 future.set(null);
             } else {
                 future.setException(new Exception("failed to delete row from content provider"));
@@ -257,11 +241,11 @@ public class MediaStoreImageProvider extends ImageProvider {
         return future;
     }
 
-    private String getVolumeName(final Activity activity, String path) {
+    private String getVolumeNameForMediaStore(@NonNull Context context, @NonNull String anyPath) {
         String volumeName = "external";
-        StorageManager sm = activity.getSystemService(StorageManager.class);
+        StorageManager sm = context.getSystemService(StorageManager.class);
         if (sm != null) {
-            StorageVolume volume = sm.getStorageVolume(new File(path));
+            StorageVolume volume = sm.getStorageVolume(new File(anyPath));
             if (volume != null && !volume.isPrimary()) {
                 String uuid = volume.getUuid();
                 if (uuid != null) {
@@ -275,20 +259,14 @@ public class MediaStoreImageProvider extends ImageProvider {
     }
 
     @Override
-    public void moveMultiple(final Activity activity, final Boolean copy, final String destinationDir, final List<AvesImageEntry> entries, @NonNull final ImageOpCallback callback) {
-        if (PermissionManager.requireVolumeAccessDialog(activity, destinationDir)) {
-            Runnable runnable = () -> moveMultiple(activity, copy, destinationDir, entries, callback);
-            new Handler(Looper.getMainLooper()).post(() -> PermissionManager.showVolumeAccessDialog(activity, destinationDir, runnable));
-            return;
-        }
-
-        DocumentFileCompat destinationDirDocFile = StorageUtils.createDirectoryIfAbsent(activity, destinationDir);
+    public void moveMultiple(final Context context, final Boolean copy, final String destinationDir, final List<AvesImageEntry> entries, @NonNull final ImageOpCallback callback) {
+        DocumentFileCompat destinationDirDocFile = StorageUtils.createDirectoryIfAbsent(context, destinationDir);
         if (destinationDirDocFile == null) {
             callback.onFailure(new Exception("failed to create directory at path=" + destinationDir));
             return;
         }
 
-        MediaStoreMoveDestination destination = new MediaStoreMoveDestination(activity, destinationDir);
+        MediaStoreMoveDestination destination = new MediaStoreMoveDestination(context, destinationDir);
         if (destination.volumePath == null) {
             callback.onFailure(new Exception("failed to set up destination volume path for path=" + destinationDir));
             return;
@@ -303,14 +281,14 @@ public class MediaStoreImageProvider extends ImageProvider {
                 put("uri", sourceUri.toString());
             }};
 
-            // TODO TLAD check if there is any downside to use tree document files with scoped storage on API 30+
-            // when testing scoped storage on API 29, it seems less constraining to use tree document files than to rely on the Media Store
+            // on API 30 we cannot get access granted directly to a volume root from its document tree,
+            // but it is still less constraining to use tree document files than to rely on the Media Store
             try {
                 ListenableFuture<Map<String, Object>> newFieldsFuture;
 //                if (Build.VERSION.SDK_INT > Build.VERSION_CODES.Q) {
-//                    newFieldsFuture = moveSingleByMediaStoreInsert(activity, sourcePath, sourceUri, destination, mimeType, copy);
+//                    newFieldsFuture = moveSingleByMediaStoreInsert(context, sourcePath, sourceUri, destination, mimeType, copy);
 //                } else {
-                newFieldsFuture = moveSingleByTreeDocAndScan(activity, sourcePath, sourceUri, destinationDir, destinationDirDocFile, mimeType, copy);
+                newFieldsFuture = moveSingleByTreeDocAndScan(context, sourcePath, sourceUri, destinationDir, destinationDirDocFile, mimeType, copy);
 //                }
                 Map<String, Object> newFields = newFieldsFuture.get();
                 result.put("success", true);
@@ -330,7 +308,7 @@ public class MediaStoreImageProvider extends ImageProvider {
     // - there is no documentation regarding support for usage with removable storage
     // - the Media Store only allows inserting in specific primary directories ("DCIM", "Pictures") when using scoped storage
     @RequiresApi(api = Build.VERSION_CODES.Q)
-    private ListenableFuture<Map<String, Object>> moveSingleByMediaStoreInsert(final Activity activity, final String sourcePath, final Uri sourceUri,
+    private ListenableFuture<Map<String, Object>> moveSingleByMediaStoreInsert(final Context context, final String sourcePath, final Uri sourceUri,
                                                                                final MediaStoreMoveDestination destination, final String mimeType, final boolean copy) {
         SettableFuture<Map<String, Object>> future = SettableFuture.create();
 
@@ -344,22 +322,23 @@ public class MediaStoreImageProvider extends ImageProvider {
             // from API 29, changing MediaColumns.RELATIVE_PATH can move files on disk (same storage device)
             contentValues.put(MediaStore.MediaColumns.RELATIVE_PATH, destination.relativePath);
             contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME, displayName);
+            String volumeName = destination.volumeNameForMediaStore;
             Uri tableUrl = mimeType.startsWith(MimeTypes.VIDEO) ?
-                    MediaStore.Video.Media.getContentUri(destination.volumeName) :
-                    MediaStore.Images.Media.getContentUri(destination.volumeName);
-            Uri destinationUri = activity.getContentResolver().insert(tableUrl, contentValues);
+                    MediaStore.Video.Media.getContentUri(volumeName) :
+                    MediaStore.Images.Media.getContentUri(volumeName);
+            Uri destinationUri = context.getContentResolver().insert(tableUrl, contentValues);
             if (destinationUri == null) {
                 future.setException(new Exception("failed to insert row to content resolver"));
             } else {
-                DocumentFileCompat sourceFile = DocumentFileCompat.fromSingleUri(activity, sourceUri);
-                DocumentFileCompat destinationFile = DocumentFileCompat.fromSingleUri(activity, destinationUri);
+                DocumentFileCompat sourceFile = DocumentFileCompat.fromSingleUri(context, sourceUri);
+                DocumentFileCompat destinationFile = DocumentFileCompat.fromSingleUri(context, destinationUri);
                 sourceFile.copyTo(destinationFile);
 
                 boolean deletedSource = false;
                 if (!copy) {
                     // delete original entry
                     try {
-                        delete(activity, sourcePath, sourceUri).get();
+                        delete(context, sourcePath, sourceUri).get();
                         deletedSource = true;
                     } catch (ExecutionException | InterruptedException e) {
                         Log.w(LOG_TAG, "failed to delete entry with path=" + sourcePath, e);
@@ -384,7 +363,7 @@ public class MediaStoreImageProvider extends ImageProvider {
     // We can create an item via `DocumentFile.createFile()`, but:
     // - we need to scan the file to get the Media Store content URI
     // - the underlying document provider controls the new file name
-    private ListenableFuture<Map<String, Object>> moveSingleByTreeDocAndScan(final Activity activity, final String sourcePath, final Uri sourceUri, final String destinationDir, final DocumentFileCompat destinationDirDocFile, final String mimeType, boolean copy) {
+    private ListenableFuture<Map<String, Object>> moveSingleByTreeDocAndScan(final Context context, final String sourcePath, final Uri sourceUri, final String destinationDir, final DocumentFileCompat destinationDirDocFile, final String mimeType, boolean copy) {
         SettableFuture<Map<String, Object>> future = SettableFuture.create();
 
         try {
@@ -396,12 +375,12 @@ public class MediaStoreImageProvider extends ImageProvider {
             // through a document URI, not a tree URI
             // note that `DocumentFile.getParentFile()` returns null if we did not pick a tree first
             DocumentFileCompat destinationTreeFile = destinationDirDocFile.createFile(mimeType, desiredNameWithoutExtension);
-            DocumentFileCompat destinationDocFile = DocumentFileCompat.fromSingleUri(activity, destinationTreeFile.getUri());
+            DocumentFileCompat destinationDocFile = DocumentFileCompat.fromSingleUri(context, destinationTreeFile.getUri());
 
             // `DocumentsContract.moveDocument()` needs `sourceParentDocumentUri`, which could be different for each entry
             // `DocumentsContract.copyDocument()` yields "Unsupported call: android:copyDocument"
             // when used with entry URI as `sourceDocumentUri`, and destinationDirDocFile URI as `targetParentDocumentUri`
-            DocumentFileCompat source = DocumentFileCompat.fromSingleUri(activity, sourceUri);
+            DocumentFileCompat source = DocumentFileCompat.fromSingleUri(context, sourceUri);
             source.copyTo(destinationDocFile);
 
             // the source file name and the created document file name can be different when:
@@ -414,7 +393,7 @@ public class MediaStoreImageProvider extends ImageProvider {
             if (!copy) {
                 // delete original entry
                 try {
-                    delete(activity, sourcePath, sourceUri).get();
+                    delete(context, sourcePath, sourceUri).get();
                     deletedSource = true;
                 } catch (ExecutionException | InterruptedException e) {
                     Log.w(LOG_TAG, "failed to delete entry with path=" + sourcePath, e);
@@ -422,7 +401,7 @@ public class MediaStoreImageProvider extends ImageProvider {
             }
 
             boolean finalDeletedSource = deletedSource;
-            scanNewPath(activity, destinationFullPath, mimeType, new ImageProvider.ImageOpCallback() {
+            scanNewPath(context, destinationFullPath, mimeType, new ImageProvider.ImageOpCallback() {
                 @Override
                 public void onSuccess(Map<String, Object> newFields) {
                     newFields.put("deletedSource", finalDeletedSource);
@@ -451,15 +430,15 @@ public class MediaStoreImageProvider extends ImageProvider {
     }
 
     class MediaStoreMoveDestination {
-        final String volumeName;
+        final String volumeNameForMediaStore;
         final String volumePath;
         final String relativePath;
         final String fullPath;
 
-        MediaStoreMoveDestination(Activity activity, String destinationDir) {
+        MediaStoreMoveDestination(@NonNull Context context, @NonNull String destinationDir) {
             fullPath = destinationDir;
-            volumeName = getVolumeName(activity, destinationDir);
-            volumePath = StorageUtils.getVolumePath(activity, destinationDir).orElse(null);
+            volumeNameForMediaStore = getVolumeNameForMediaStore(context, destinationDir);
+            volumePath = StorageUtils.getVolumePath(context, destinationDir).orElse(null);
             relativePath = volumePath != null ? destinationDir.replaceFirst(volumePath, "") : null;
         }
     }

android/app/src/main/java/deckers/thibault/aves/utils/PermissionManager.java

@@ -1,6 +1,7 @@
 package deckers.thibault.aves.utils;
 
 import android.app.Activity;
+import android.content.Context;
 import android.content.Intent;
 import android.content.UriPermission;
 import android.net.Uri;
@@ -11,12 +12,19 @@ import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
-import androidx.appcompat.app.AlertDialog;
 import androidx.core.app.ActivityCompat;
 
+import com.google.common.base.Splitter;
+
 import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 public class PermissionManager {
@@ -27,40 +35,15 @@ public class PermissionManager {
     // permission request code to pending runnable
     private static ConcurrentHashMap<Integer, PendingPermissionHandler> pendingPermissionMap = new ConcurrentHashMap<>();
 
-    public static boolean requireVolumeAccessDialog(Activity activity, @NonNull String anyPath) {
-        return StorageUtils.requireAccessPermission(anyPath) && getVolumeTreeUri(activity, anyPath) == null;
-    }
-
-    // check access permission to volume root directory & return its tree URI if available
-    @Nullable
-    public static Uri getVolumeTreeUri(Activity activity, @NonNull String anyPath) {
-        String volumeTreeUri = StorageUtils.getVolumeTreeUriForPath(activity, anyPath).orElse(null);
-        Optional<UriPermission> uriPermissionOptional = activity.getContentResolver().getPersistedUriPermissions().stream()
-                .filter(uriPermission -> uriPermission.getUri().toString().equals(volumeTreeUri))
-                .findFirst();
-        return uriPermissionOptional.map(UriPermission::getUri).orElse(null);
-    }
-
-    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
-    public static void showVolumeAccessDialog(final Activity activity, @NonNull String anyPath, final Runnable pendingRunnable) {
-        String volumePath = StorageUtils.getVolumePath(activity, anyPath).orElse(null);
-        // TODO TLAD show volume name/ID in the message
-        new AlertDialog.Builder(activity)
-                .setTitle("Storage Volume Access")
-                .setMessage("Please select the root directory of the storage volume in the next screen, so that this app has permission to access it and complete your request.")
-                .setPositiveButton(android.R.string.ok, (dialog, button) -> requestVolumeAccess(activity, volumePath, pendingRunnable, null))
-                .show();
-    }
-
-    public static void requestVolumeAccess(Activity activity, String volumePath, Runnable onGranted, Runnable onDenied) {
-        Log.i(LOG_TAG, "request user to select and grant access permission to volume=" + volumePath);
-        pendingPermissionMap.put(VOLUME_ROOT_PERMISSION_REQUEST_CODE, new PendingPermissionHandler(volumePath, onGranted, onDenied));
+    public static void requestVolumeAccess(@NonNull Activity activity, @NonNull String path, @NonNull Runnable onGranted, @NonNull Runnable onDenied) {
+        Log.i(LOG_TAG, "request user to select and grant access permission to volume=" + path);
+        pendingPermissionMap.put(VOLUME_ROOT_PERMISSION_REQUEST_CODE, new PendingPermissionHandler(path, onGranted, onDenied));
 
         Intent intent = null;
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q && volumePath != null) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             StorageManager sm = activity.getSystemService(StorageManager.class);
             if (sm != null) {
-                StorageVolume volume = sm.getStorageVolume(new File(volumePath));
+                StorageVolume volume = sm.getStorageVolume(new File(path));
                 if (volume != null) {
                     intent = volume.createOpenDocumentTreeIntent();
                 }
@@ -75,25 +58,109 @@ public class PermissionManager {
         ActivityCompat.startActivityForResult(activity, intent, VOLUME_ROOT_PERMISSION_REQUEST_CODE, null);
     }
 
-    public static void onPermissionResult(Activity activity, int requestCode, boolean granted, Uri treeUri) {
-        Log.d(LOG_TAG, "onPermissionResult with requestCode=" + requestCode + ", granted=" + granted);
+    public static void onPermissionResult(int requestCode, @Nullable Uri treeUri) {
+        Log.d(LOG_TAG, "onPermissionResult with requestCode=" + requestCode + ", treeUri=" + treeUri);
+        boolean granted = treeUri != null;
 
         PendingPermissionHandler handler = pendingPermissionMap.remove(requestCode);
         if (handler == null) return;
-        StorageUtils.setVolumeTreeUri(activity, handler.volumePath, treeUri.toString());
 
         Runnable runnable = granted ? handler.onGranted : handler.onDenied;
         if (runnable == null) return;
         runnable.run();
     }
 
-    static class PendingPermissionHandler {
-        String volumePath;
-        Runnable onGranted;
-        Runnable onDenied;
+    public static Optional<String> getGrantedDirForPath(@NonNull Context context, @NonNull String anyPath) {
+        return getGrantedDirs(context).stream().filter(anyPath::startsWith).findFirst();
+    }
 
-        PendingPermissionHandler(String volumePath, Runnable onGranted, Runnable onDenied) {
-            this.volumePath = volumePath;
+    public static List<Map<String, String>> getInaccessibleDirectories(@NonNull Context context, @NonNull List<String> dirPaths) {
+        Set<String> grantedDirs = getGrantedDirs(context);
+
+        // find set of inaccessible directories for each volume
+        Map<String, Set<String>> dirsPerVolume = new HashMap<>();
+        for (String dirPath : dirPaths) {
+            if (!dirPath.endsWith(File.separator)) {
+                dirPath += File.separator;
+            }
+            if (grantedDirs.stream().noneMatch(dirPath::startsWith)) {
+                // inaccessible dirs
+                StorageUtils.PathSegments segments = new StorageUtils.PathSegments(context, dirPath);
+                Set<String> dirSet = dirsPerVolume.getOrDefault(segments.volumePath, new HashSet<>());
+                if (dirSet != null) {
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+                        // request primary directory on volume from Android R
+                        String relativeDir = segments.relativeDir;
+                        if (relativeDir != null) {
+                            Iterator<String> iterator = Splitter.on(File.separatorChar).omitEmptyStrings().split(relativeDir).iterator();
+                            if (iterator.hasNext()) {
+                                // primary dir
+                                dirSet.add(iterator.next());
+                            }
+                        }
+                    } else {
+                        // request volume root until Android Q
+                        dirSet.add("");
+                    }
+                }
+                dirsPerVolume.put(segments.volumePath, dirSet);
+            }
+        }
+
+        // format for easier handling on Flutter
+        List<Map<String, String>> inaccessibleDirs = new ArrayList<>();
+        StorageManager sm = context.getSystemService(StorageManager.class);
+        if (sm != null) {
+            for (Map.Entry<String, Set<String>> volumeEntry : dirsPerVolume.entrySet()) {
+                String volumePath = volumeEntry.getKey();
+                String volumeDescription = "";
+                try {
+                    StorageVolume volume = sm.getStorageVolume(new File(volumePath));
+                    if (volume != null) {
+                        volumeDescription = volume.getDescription(context);
+                    }
+                } catch (IllegalArgumentException e) {
+                    // ignore
+                }
+                for (String relativeDir : volumeEntry.getValue()) {
+                    HashMap<String, String> dirMap = new HashMap<>();
+                    dirMap.put("volumePath", volumePath);
+                    dirMap.put("volumeDescription", volumeDescription);
+                    dirMap.put("relativeDir", relativeDir);
+                    inaccessibleDirs.add(dirMap);
+                }
+            }
+        }
+        Log.d(LOG_TAG, "getInaccessibleDirectories dirPaths=" + dirPaths + " -> inaccessibleDirs=" + inaccessibleDirs);
+        return inaccessibleDirs;
+    }
+
+    private static Set<String> getGrantedDirs(Context context) {
+        HashSet<String> accessibleDirs = new HashSet<>();
+
+        // find paths matching URIs granted by the user
+        for (UriPermission uriPermission : context.getContentResolver().getPersistedUriPermissions()) {
+            Optional<String> dirPath = StorageUtils.convertTreeUriToDirPath(context, uriPermission.getUri());
+            dirPath.ifPresent(accessibleDirs::add);
+        }
+
+        // from Android R, we no longer have access permission by default on primary volume
+        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.Q) {
+            String primaryPath = StorageUtils.getPrimaryVolumePath();
+            accessibleDirs.add(primaryPath);
+        }
+
+        Log.d(LOG_TAG, "getGrantedDirs accessibleDirs=" + accessibleDirs);
+        return accessibleDirs;
+    }
+
+    static class PendingPermissionHandler {
+        final String path;
+        final Runnable onGranted; // user gave access to a directory, with no guarantee that it matches the specified `path`
+        final Runnable onDenied; // user cancelled
+
+        PendingPermissionHandler(@NonNull String path, @NonNull Runnable onGranted, @NonNull Runnable onDenied) {
+            this.path = path;
             this.onGranted = onGranted;
             this.onDenied = onDenied;
         }

android/app/src/main/java/deckers/thibault/aves/utils/StorageUtils.java

@@ -1,14 +1,15 @@
 package deckers.thibault.aves.utils;
 
 import android.annotation.SuppressLint;
-import android.app.Activity;
 import android.content.ContentResolver;
 import android.content.Context;
-import android.content.SharedPreferences;
 import android.media.MediaMetadataRetriever;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Environment;
+import android.os.storage.StorageManager;
+import android.os.storage.StorageVolume;
+import android.provider.DocumentsContract;
 import android.provider.MediaStore;
 import android.text.TextUtils;
 import android.util.Log;
@@ -21,9 +22,6 @@ import com.commonsware.cwac.document.DocumentFileCompat;
 import com.google.common.base.Splitter;
 import com.google.common.collect.Lists;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -31,12 +29,13 @@ import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
-import java.util.Map;
+import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public class StorageUtils {
     private static final String LOG_TAG = Utils.createLogTag(StorageUtils.class);
@@ -51,35 +50,37 @@ public class StorageUtils {
     // primary volume path, with trailing "/"
     private static String mPrimaryVolumePath;
 
-    private static String getPrimaryVolumePath() {
+    public static String getPrimaryVolumePath() {
         if (mPrimaryVolumePath == null) {
             mPrimaryVolumePath = findPrimaryVolumePath();
         }
         return mPrimaryVolumePath;
     }
 
-    public static String[] getVolumePaths(Context context) {
+    public static String[] getVolumePaths(@NonNull Context context) {
         if (mStorageVolumePaths == null) {
             mStorageVolumePaths = findVolumePaths(context);
         }
         return mStorageVolumePaths;
     }
 
-    public static Optional<String> getVolumePath(Context context, @NonNull String anyPath) {
+    public static Optional<String> getVolumePath(@NonNull Context context, @NonNull String anyPath) {
         return Arrays.stream(getVolumePaths(context)).filter(anyPath::startsWith).findFirst();
     }
 
     @Nullable
-    private static Iterator<String> getPathStepIterator(Context context, @NonNull String anyPath) {
-        Optional<String> volumePathOpt = getVolumePath(context, anyPath);
-        if (!volumePathOpt.isPresent()) return null;
+    private static Iterator<String> getPathStepIterator(@NonNull Context context, @NonNull String anyPath, @Nullable String root) {
+        if (root == null) {
+            root = getVolumePath(context, anyPath).orElse(null);
+            if (root == null) return null;
+        }
 
         String relativePath = null, filename = null;
         int lastSeparatorIndex = anyPath.lastIndexOf(File.separator) + 1;
-        int volumePathLength = volumePathOpt.get().length();
-        if (lastSeparatorIndex > volumePathLength) {
+        int rootLength = root.length();
+        if (lastSeparatorIndex > rootLength) {
             filename = anyPath.substring(lastSeparatorIndex);
-            relativePath = anyPath.substring(volumePathLength, lastSeparatorIndex);
+            relativePath = anyPath.substring(rootLength, lastSeparatorIndex);
         }
         if (relativePath == null) return null;
 
@@ -119,7 +120,21 @@ public class StorageUtils {
         if (TextUtils.isEmpty(rawEmulatedStorageTarget)) {
             // fix of empty raw emulated storage on marshmallow
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                File[] files = context.getExternalFilesDirs(null);
+                List<File> files;
+                boolean validFiles;
+                do {
+                    // `getExternalFilesDirs` sometimes include `null` when called right after getting read access
+                    // (e.g. on API 30 emulator) so we retry until the file system is ready
+                    files = Arrays.asList(context.getExternalFilesDirs(null));
+                    validFiles = !files.contains(null);
+                    if (!validFiles) {
+                        try {
+                            Thread.sleep(100);
+                        } catch (InterruptedException e) {
+                            Log.e(LOG_TAG, "insomnia", e);
+                        }
+                    }
+                } while (!validFiles);
                 for (File file : files) {
                     String applicationSpecificAbsolutePath = file.getAbsolutePath();
                     String emulatedRootPath = applicationSpecificAbsolutePath.substring(0, applicationSpecificAbsolutePath.indexOf("Android/data"));
@@ -210,43 +225,86 @@ public class StorageUtils {
      * Volume tree URIs
      */
 
-    // serialized map from storage volume paths to their document tree URIs, from the Documents Provider
-    // e.g. "/storage/12A9-8B42" -> "content://com.android.externalstorage.documents/tree/12A9-8B42%3A"
-    private static final String PREF_VOLUME_TREE_URIS = "volume_tree_uris";
-
-    public static void setVolumeTreeUri(Activity activity, String volumePath, String treeUri) {
-        Map<String, String> map = getVolumeTreeUris(activity);
-        map.put(volumePath, treeUri);
-
-        SharedPreferences.Editor editor = activity.getPreferences(Context.MODE_PRIVATE).edit();
-        String json = new JSONObject(map).toString();
-        editor.putString(PREF_VOLUME_TREE_URIS, json);
-        editor.apply();
+    private static Optional<String> getVolumeUuidForTreeUri(@NonNull Context context, @NonNull String anyPath) {
+        StorageManager sm = context.getSystemService(StorageManager.class);
+        if (sm != null) {
+            StorageVolume volume = sm.getStorageVolume(new File(anyPath));
+            if (volume != null) {
+                if (volume.isPrimary()) {
+                    return Optional.of("primary");
+                }
+                String uuid = volume.getUuid();
+                if (uuid != null) {
+                    return Optional.of(uuid.toUpperCase());
+                }
+            }
+        }
+        Log.e(LOG_TAG, "failed to find volume UUID for anyPath=" + anyPath);
+        return Optional.empty();
     }
 
-    private static Map<String, String> getVolumeTreeUris(Activity activity) {
-        Map<String, String> map = new HashMap<>();
-
-        SharedPreferences preferences = activity.getPreferences(Context.MODE_PRIVATE);
-        String json = preferences.getString(PREF_VOLUME_TREE_URIS, new JSONObject().toString());
-        if (json != null) {
+    private static Optional<String> getVolumePathFromTreeUriUuid(@NonNull Context context, @NonNull String uuid) {
+        if (uuid.equals("primary")) {
+            return Optional.of(getPrimaryVolumePath());
+        }
+        StorageManager sm = context.getSystemService(StorageManager.class);
+        if (sm != null) {
+            for (String volumePath : StorageUtils.getVolumePaths(context)) {
                 try {
-                JSONObject jsonObject = new JSONObject(json);
-                Iterator<String> iterator = jsonObject.keys();
-                while (iterator.hasNext()) {
-                    String k = iterator.next();
-                    String v = (String) jsonObject.get(k);
-                    map.put(k, v);
+                    StorageVolume volume = sm.getStorageVolume(new File(volumePath));
+                    if (volume != null && uuid.equalsIgnoreCase(volume.getUuid())) {
+                        return Optional.of(volumePath);
                     }
-            } catch (JSONException e) {
-                Log.w(LOG_TAG, "failed to read volume tree URIs from preferences", e);
+                } catch (IllegalArgumentException e) {
+                    // ignore
                 }
             }
-        return map;
+        }
+        Log.e(LOG_TAG, "failed to find volume path for UUID=" + uuid);
+        return Optional.empty();
     }
 
-    public static Optional<String> getVolumeTreeUriForPath(Activity activity, String anyPath) {
-        return StorageUtils.getVolumePath(activity, anyPath).map(volumePath -> getVolumeTreeUris(activity).get(volumePath));
+    // e.g.
+    // /storage/emulated/0/         -> content://com.android.externalstorage.documents/tree/primary%3A
+    // /storage/10F9-3F13/Pictures/ -> content://com.android.externalstorage.documents/tree/10F9-3F13%3APictures
+    static Optional<Uri> convertDirPathToTreeUri(@NonNull Context context, @NonNull String dirPath) {
+        Optional<String> uuid = getVolumeUuidForTreeUri(context, dirPath);
+        if (uuid.isPresent()) {
+            String relativeDir = new PathSegments(context, dirPath).relativeDir;
+            if (relativeDir == null) {
+                relativeDir = "";
+            } else if (relativeDir.endsWith(File.separator)) {
+                relativeDir = relativeDir.substring(0, relativeDir.length() - 1);
+            }
+            Uri treeUri = DocumentsContract.buildTreeDocumentUri("com.android.externalstorage.documents", uuid.get() + ":" + relativeDir);
+            return Optional.of(treeUri);
+        }
+        Log.e(LOG_TAG, "failed to convert dirPath=" + dirPath + " to tree URI");
+        return Optional.empty();
+    }
+
+    // e.g.
+    // content://com.android.externalstorage.documents/tree/primary%3A              -> /storage/emulated/0/
+    // content://com.android.externalstorage.documents/tree/10F9-3F13%3APictures    -> /storage/10F9-3F13/Pictures/
+    static Optional<String> convertTreeUriToDirPath(@NonNull Context context, @NonNull Uri treeUri) {
+        String encoded = treeUri.toString().substring("content://com.android.externalstorage.documents/tree/".length());
+        Matcher matcher = Pattern.compile("(.*?):(.*)").matcher(Uri.decode(encoded));
+        if (matcher.find()) {
+            String uuid = matcher.group(1);
+            String relativePath = matcher.group(2);
+            if (uuid != null && relativePath != null) {
+                Optional<String> volumePath = getVolumePathFromTreeUriUuid(context, uuid);
+                if (volumePath.isPresent()) {
+                    String dirPath = volumePath.get() + relativePath;
+                    if (!dirPath.endsWith(File.separator)) {
+                        dirPath += File.separator;
+                    }
+                    return Optional.of(dirPath);
+                }
+            }
+        }
+        Log.e(LOG_TAG, "failed to convert treeUri=" + treeUri + " to path");
+        return Optional.empty();
     }
 
     /**
@@ -254,20 +312,22 @@ public class StorageUtils {
      */
 
     @Nullable
-    public static DocumentFileCompat getDocumentFile(@NonNull Activity activity, @NonNull String anyPath, @NonNull Uri mediaUri) {
+    public static DocumentFileCompat getDocumentFile(@NonNull Context context, @NonNull String anyPath, @NonNull Uri mediaUri) {
         if (requireAccessPermission(anyPath)) {
             // need a document URI (not a media content URI) to open a `DocumentFile` output stream
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                 // cleanest API to get it
-                Uri docUri = MediaStore.getDocumentUri(activity, mediaUri);
+                Uri docUri = MediaStore.getDocumentUri(context, mediaUri);
                 if (docUri != null) {
-                    return DocumentFileCompat.fromSingleUri(activity, docUri);
+                    return DocumentFileCompat.fromSingleUri(context, docUri);
                 }
             }
             // fallback for older APIs
-            Uri volumeTreeUri = PermissionManager.getVolumeTreeUri(activity, anyPath);
-            Optional<DocumentFileCompat> docFile = getDocumentFileFromVolumeTree(activity, volumeTreeUri, anyPath);
-            return docFile.orElse(null);
+            return getVolumePath(context, anyPath)
+                    .flatMap(volumePath -> convertDirPathToTreeUri(context, volumePath)
+                            .flatMap(treeUri -> getDocumentFileFromVolumeTree(context, treeUri, anyPath)))
+                    .orElse(null);
+
         }
         // good old `File`
         return DocumentFileCompat.fromFile(new File(anyPath));
@@ -275,16 +335,21 @@ public class StorageUtils {
 
     // returns the directory `DocumentFile` (from tree URI when scoped storage is required, `File` otherwise)
     // returns null if directory does not exist and could not be created
-    public static DocumentFileCompat createDirectoryIfAbsent(@NonNull Activity activity, @NonNull String directoryPath) {
-        if (requireAccessPermission(directoryPath)) {
-            Uri rootTreeUri = PermissionManager.getVolumeTreeUri(activity, directoryPath);
-            DocumentFileCompat parentFile = DocumentFileCompat.fromTreeUri(activity, rootTreeUri);
+    public static DocumentFileCompat createDirectoryIfAbsent(@NonNull Context context, @NonNull String dirPath) {
+        if (!dirPath.endsWith(File.separator)) {
+            dirPath += File.separator;
+        }
+        if (requireAccessPermission(dirPath)) {
+            String grantedDir = PermissionManager.getGrantedDirForPath(context, dirPath).orElse(null);
+            if (grantedDir == null) return null;
+
+            Uri rootTreeUri = convertDirPathToTreeUri(context, grantedDir).orElse(null);
+            if (rootTreeUri == null) return null;
+
+            DocumentFileCompat parentFile = DocumentFileCompat.fromTreeUri(context, rootTreeUri);
             if (parentFile == null) return null;
 
-            if (!directoryPath.endsWith(File.separator)) {
-                directoryPath += File.separator;
-            }
-            Iterator<String> pathIterator = getPathStepIterator(activity, directoryPath);
+            Iterator<String> pathIterator = getPathStepIterator(context, dirPath, grantedDir);
             while (pathIterator != null && pathIterator.hasNext()) {
                 String dirName = pathIterator.next();
                 DocumentFileCompat dirFile = findDocumentFileIgnoreCase(parentFile, dirName);
@@ -304,10 +369,10 @@ public class StorageUtils {
             }
             return parentFile;
         } else {
-            File directory = new File(directoryPath);
+            File directory = new File(dirPath);
             if (!directory.exists()) {
                 if (!directory.mkdirs()) {
-                    Log.e(LOG_TAG, "failed to create directories at path=" + directoryPath);
+                    Log.e(LOG_TAG, "failed to create directories at path=" + dirPath);
                     return null;
                 }
             }
@@ -323,23 +388,19 @@ public class StorageUtils {
             temp.deleteOnExit();
             return temp.getPath();
         } catch (IOException e) {
-            Log.w(LOG_TAG, "failed to copy file from path=" + path);
+            Log.e(LOG_TAG, "failed to copy file from path=" + path);
         }
         return null;
     }
 
-    private static Optional<DocumentFileCompat> getDocumentFileFromVolumeTree(Context context, Uri rootTreeUri, String path) {
-        if (rootTreeUri == null || path == null) {
-            return Optional.empty();
-        }
-
+    private static Optional<DocumentFileCompat> getDocumentFileFromVolumeTree(Context context, @NonNull Uri rootTreeUri, @NonNull String anyPath) {
         DocumentFileCompat documentFile = DocumentFileCompat.fromTreeUri(context, rootTreeUri);
         if (documentFile == null) {
             return Optional.empty();
         }
 
         // follow the entry path down the document tree
-        Iterator<String> pathIterator = getPathStepIterator(context, path);
+        Iterator<String> pathIterator = getPathStepIterator(context, anyPath, null);
         while (pathIterator != null && pathIterator.hasNext()) {
             documentFile = findDocumentFileIgnoreCase(documentFile, pathIterator.next());
             if (documentFile == null) {
@@ -378,7 +439,7 @@ public class StorageUtils {
         return uri != null && ContentResolver.SCHEME_CONTENT.equalsIgnoreCase(uri.getScheme()) && MediaStore.AUTHORITY.equalsIgnoreCase(uri.getHost());
     }
 
-    public static InputStream openInputStream(Context context, Uri uri) throws FileNotFoundException {
+    public static InputStream openInputStream(@NonNull Context context, @NonNull Uri uri) throws FileNotFoundException {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             // we get a permission denial if we require original from a provider other than the media store
             if (isMediaStoreContentUri(uri)) {
@@ -388,7 +449,7 @@ public class StorageUtils {
         return context.getContentResolver().openInputStream(uri);
     }
 
-    public static MediaMetadataRetriever openMetadataRetriever(Context context, Uri uri) {
+    public static MediaMetadataRetriever openMetadataRetriever(@NonNull Context context, @NonNull Uri uri) {
         MediaMetadataRetriever retriever = new MediaMetadataRetriever();
         try {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
@@ -399,8 +460,28 @@ public class StorageUtils {
             }
             retriever.setDataSource(context, uri);
         } catch (Exception e) {
-            Log.w(LOG_TAG, "failed to open MediaMetadataRetriever for uri=" + uri, e);
+            Log.e(LOG_TAG, "failed to open MediaMetadataRetriever for uri=" + uri, e);
         }
         return retriever;
     }
+
+    public static class PathSegments {
+        String fullPath; // should match "volumePath + relativeDir + filename"
+        String volumePath; // with trailing "/"
+        String relativeDir; // with trailing "/"
+        String filename; // null for directories
+
+        PathSegments(@NonNull Context context, @NonNull String fullPath) {
+            this.fullPath = fullPath;
+            volumePath = StorageUtils.getVolumePath(context, fullPath).orElse(null);
+            if (volumePath == null) return;
+
+            int lastSeparatorIndex = fullPath.lastIndexOf(File.separator) + 1;
+            int volumePathLength = volumePath.length();
+            if (lastSeparatorIndex > volumePathLength) {
+                filename = fullPath.substring(lastSeparatorIndex);
+                relativeDir = fullPath.substring(volumePathLength, lastSeparatorIndex);
+            }
+        }
+    }
 }

lib/main.dart

@@ -45,10 +45,10 @@ class _AvesAppState extends State<AvesApp> {
         scaffoldBackgroundColor: Colors.grey[900],
         buttonColor: accentColor,
         toggleableActiveColor: accentColor,
-        tooltipTheme: const TooltipThemeData(
+        tooltipTheme: TooltipThemeData(
           verticalOffset: 32,
         ),
-        appBarTheme: const AppBarTheme(
+        appBarTheme: AppBarTheme(
           textTheme: TextTheme(
             headline6: TextStyle(
               fontSize: 20,
@@ -58,12 +58,12 @@ class _AvesAppState extends State<AvesApp> {
           ),
         ),
       ),
-      home: FutureBuilder(
+      home: FutureBuilder<void>(
         future: _appSetup,
-        builder: (context, AsyncSnapshot<void> snapshot) {
-          if (snapshot.hasError) return const Icon(AIcons.error);
-          if (snapshot.connectionState != ConnectionState.done) return const Scaffold();
-          return settings.hasAcceptedTerms ? const HomePage() : const WelcomePage();
+        builder: (context, snapshot) {
+          if (snapshot.hasError) return Icon(AIcons.error);
+          if (snapshot.connectionState != ConnectionState.done) return Scaffold();
+          return settings.hasAcceptedTerms ? HomePage() : WelcomePage();
         },
       ),
     );

lib/model/filters/mime.dart

@@ -34,7 +34,7 @@ class MimeFilter extends CollectionFilter {
       _label ??= lowMime.split('/')[0].toUpperCase();
     } else {
       _filter = (entry) => entry.mimeType == lowMime;
-      if (lowMime == MimeTypes.SVG) {
+      if (lowMime == MimeTypes.svg) {
         _label = 'SVG';
       }
       _label ??= lowMime.split('/')[1].toUpperCase();

lib/model/filters/query.dart

@@ -8,7 +8,7 @@ import 'package:flutter/widgets.dart';
 class QueryFilter extends CollectionFilter {
   static const type = 'query';
 
-  static final exactRegex = RegExp('^"(.*)"\$');
+  static final RegExp exactRegex = RegExp('^"(.*)"\$');
 
   final String query;
   final bool colorful;
@@ -39,7 +39,7 @@ class QueryFilter extends CollectionFilter {
   bool get isUnique => false;
 
   @override
-  String get label => '${query}';
+  String get label => '$query';
 
   @override
   Widget iconBuilder(BuildContext context, double size, {bool showGenericIcon = true}) => Icon(AIcons.text, size: size);

lib/model/image_entry.dart

@@ -152,10 +152,10 @@ class ImageEntry {
 
   bool get isFavourite => favourites.isFavourite(this);
 
-  bool get isSvg => mimeType == MimeTypes.SVG;
+  bool get isSvg => mimeType == MimeTypes.svg;
 
   // guess whether this is a photo, according to file type (used as a hint to e.g. display megapixels)
-  bool get isPhoto => [MimeTypes.HEIC, MimeTypes.HEIF, MimeTypes.JPEG].contains(mimeType);
+  bool get isPhoto => [MimeTypes.heic, MimeTypes.heif, MimeTypes.jpeg].contains(mimeType);
 
   bool get isVideo => mimeType.startsWith('video');
 
@@ -167,7 +167,7 @@ class ImageEntry {
 
   bool get canPrint => !isVideo;
 
-  bool get canRotate => canEdit && (mimeType == MimeTypes.JPEG || mimeType == MimeTypes.PNG);
+  bool get canRotate => canEdit && (mimeType == MimeTypes.jpeg || mimeType == MimeTypes.png);
 
   bool get rotated => ((isVideo && isCatalogued) ? _catalogMetadata.videoRotation : orientationDegrees) % 180 == 90;
 
@@ -270,7 +270,7 @@ class ImageEntry {
 
     final coordinates = Coordinates(latitude, longitude);
     try {
-      final call = () => Geocoder.local.findAddressesFromCoordinates(coordinates);
+      Future<List<Address>> call() => Geocoder.local.findAddressesFromCoordinates(coordinates);
       final addresses = await (background
           ? servicePolicy.call(
               call,

lib/model/image_metadata.dart

@@ -179,11 +179,12 @@ class AddressDetails {
   }
 }
 
+@immutable
 class FavouriteRow {
   final int contentId;
   final String path;
 
-  FavouriteRow({
+  const FavouriteRow({
     this.contentId,
     this.path,
   });

lib/model/mime_types.dart

@@ -1,15 +1,15 @@
 class MimeTypes {
-  static const String ANY_IMAGE = 'image/*';
-  static const String GIF = 'image/gif';
-  static const String HEIC = 'image/heic';
-  static const String HEIF = 'image/heif';
-  static const String JPEG = 'image/jpeg';
-  static const String PNG = 'image/png';
-  static const String SVG = 'image/svg+xml';
-  static const String WEBP = 'image/webp';
+  static const String anyImage = 'image/*';
+  static const String gif = 'image/gif';
+  static const String heic = 'image/heic';
+  static const String heif = 'image/heif';
+  static const String jpeg = 'image/jpeg';
+  static const String png = 'image/png';
+  static const String svg = 'image/svg+xml';
+  static const String webp = 'image/webp';
 
-  static const String ANY_VIDEO = 'video/*';
-  static const String AVI = 'video/avi';
-  static const String MP2T = 'video/mp2t'; // .m2ts
-  static const String MP4 = 'video/mp4';
+  static const String anyVideo = 'video/*';
+  static const String avi = 'video/avi';
+  static const String mp2t = 'video/mp2t'; // .m2ts
+  static const String mp4 = 'video/mp4';
 }

lib/model/settings.dart

@@ -76,6 +76,7 @@ class Settings {
 
   // convenience methods
 
+  // ignore: avoid_positional_boolean_parameters
   bool getBoolOrDefault(String key, bool defaultValue) => _prefs.getKeys().contains(key) ? _prefs.getBool(key) : defaultValue;
 
   T getEnumOrDefault<T>(String key, T defaultValue, Iterable<T> values) {

lib/model/source/collection_lens.dart

@@ -168,8 +168,8 @@ class CollectionLens with ChangeNotifier, CollectionActivityMixin, CollectionSel
         ]);
         break;
       case SortFactor.name:
-        final byAlbum = groupBy(_filteredEntries, (ImageEntry entry) => entry.directory);
-        final compare = (a, b) {
+        final byAlbum = groupBy<ImageEntry, String>(_filteredEntries, (entry) => entry.directory);
+        int compare(a, b) {
           final ua = source.getUniqueAlbumName(a);
           final ub = source.getUniqueAlbumName(b);
           final c = compareAsciiUpperCase(ua, ub);
@@ -177,7 +177,7 @@ class CollectionLens with ChangeNotifier, CollectionActivityMixin, CollectionSel
           final va = androidFileUtils.getStorageVolume(a)?.path ?? '';
           final vb = androidFileUtils.getStorageVolume(b)?.path ?? '';
           return compareAsciiUpperCase(va, vb);
-        };
+        }
         sections = SplayTreeMap.of(byAlbum, compare);
         break;
     }

lib/model/source/collection_source.dart

@@ -63,7 +63,7 @@ class CollectionSource with SourceBase, AlbumMixin, LocationMixin, TagMixin {
     _rawEntries.addAll(entries);
     addFolderPath(_rawEntries.map((entry) => entry.directory));
     invalidateFilterEntryCounts();
-    eventBus.fire(const EntryAddedEvent());
+    eventBus.fire(EntryAddedEvent());
   }
 
   void removeEntries(Iterable<ImageEntry> entries) {

lib/model/source/location.dart

@@ -57,6 +57,7 @@ mixin LocationMixin on SourceBase {
         newAddresses.add(entry.addressDetails);
         if (newAddresses.length >= _commitCountThreshold) {
           await metadataDb.saveAddresses(List.unmodifiable(newAddresses));
+          onAddressMetadataChanged();
           newAddresses.clear();
         }
       }
@@ -74,7 +75,7 @@ mixin LocationMixin on SourceBase {
 
   void updateLocations() {
     final locations = rawEntries.where((entry) => entry.isLocated).map((entry) => entry.addressDetails).toList();
-    final lister = (String Function(AddressDetails a) f) => List<String>.unmodifiable(locations.map(f).where((s) => s != null && s.isNotEmpty).toSet().toList()..sort(compareAsciiUpperCase));
+    List<String> lister(String Function(AddressDetails a) f) => List<String>.unmodifiable(locations.map(f).where((s) => s != null && s.isNotEmpty).toSet().toList()..sort(compareAsciiUpperCase));
     sortedCountries = lister((address) => '${address.countryName};${address.countryCode}');
     sortedPlaces = lister((address) => address.place);
 

lib/model/source/tag.dart

@@ -23,7 +23,7 @@ mixin TagMixin on SourceBase {
 
   Future<void> catalogEntries() async {
 //    final stopwatch = Stopwatch()..start();
-    final todo = rawEntries.where((entry) => !entry.isCatalogued).toList();
+    final todo = rawEntries.where((entry) => !entry.isCatalogued && !entry.isSvg).toList();
     if (todo.isEmpty) return;
 
     var progressDone = 0;
@@ -37,6 +37,7 @@ mixin TagMixin on SourceBase {
         newMetadata.add(entry.catalogMetadata);
         if (newMetadata.length >= _commitCountThreshold) {
           await metadataDb.saveMetadata(List.unmodifiable(newMetadata));
+          onCatalogMetadataChanged();
           newMetadata.clear();
         }
       }

lib/services/android_app_service.dart

@@ -88,7 +88,7 @@ class AndroidAppService {
     }
   }
 
-  static Future<void> share(Set<ImageEntry> entries) async {
+  static Future<void> share(Iterable<ImageEntry> entries) async {
     // loosen mime type to a generic one, so we can share with badly defined apps
     // e.g. Google Lens declares receiving "image/jpeg" only, but it can actually handle more formats
     final urisByMimeType = groupBy<ImageEntry, String>(entries, (e) => e.mimeTypeAnySubtype).map((k, v) => MapEntry(k, v.map((e) => e.uri).toList()));

lib/services/android_file_service.dart

@@ -18,16 +18,18 @@ class AndroidFileService {
     return [];
   }
 
-  static Future<bool> requireVolumeAccessDialog(String path) async {
+  // returns a list of directories,
+  // each directory is a map with "volumePath", "volumeDescription", "relativeDir"
+  static Future<List<Map>> getInaccessibleDirectories(Iterable<String> dirPaths) async {
     try {
-      final result = await platform.invokeMethod('requireVolumeAccessDialog', <String, dynamic>{
-        'path': path,
+      final result = await platform.invokeMethod('getInaccessibleDirectories', <String, dynamic>{
+        'dirPaths': dirPaths.toList(),
       });
-      return result as bool;
+      return (result as List).cast<Map>();
     } on PlatformException catch (e) {
-      debugPrint('requireVolumeAccessDialog failed with code=${e.code}, exception=${e.message}, details=${e.details}}');
+      debugPrint('getInaccessibleDirectories failed with code=${e.code}, exception=${e.message}, details=${e.details}}');
     }
-    return false;
+    return null;
   }
 
   // returns whether user granted access to volume root at `volumePath`

lib/services/image_file_service.dart

@@ -140,7 +140,7 @@ class ImageFileService {
     try {
       return opChannel.receiveBroadcastStream(<String, dynamic>{
         'op': 'delete',
-        'entries': entries.map((entry) => _toPlatformEntryMap(entry)).toList(),
+        'entries': entries.map(_toPlatformEntryMap).toList(),
       }).map((event) => ImageOpEvent.fromMap(event));
     } on PlatformException catch (e) {
       debugPrint('delete failed with code=${e.code}, exception=${e.message}, details=${e.details}');
@@ -153,7 +153,7 @@ class ImageFileService {
     try {
       return opChannel.receiveBroadcastStream(<String, dynamic>{
         'op': 'move',
-        'entries': entries.map((entry) => _toPlatformEntryMap(entry)).toList(),
+        'entries': entries.map(_toPlatformEntryMap).toList(),
         'copy': copy,
         'destinationPath': destinationAlbum,
       }).map((event) => MoveOpEvent.fromMap(event));
@@ -192,11 +192,12 @@ class ImageFileService {
   }
 }
 
+@immutable
 class ImageOpEvent {
   final bool success;
   final String uri;
 
-  ImageOpEvent({
+  const ImageOpEvent({
     this.success,
     this.uri,
   });
@@ -226,7 +227,7 @@ class ImageOpEvent {
 class MoveOpEvent extends ImageOpEvent {
   final Map newFields;
 
-  MoveOpEvent({bool success, String uri, this.newFields})
+  const MoveOpEvent({bool success, String uri, this.newFields})
       : super(
           success: success,
           uri: uri,

lib/services/metadata_service.dart

@@ -26,7 +26,7 @@ class MetadataService {
   static Future<CatalogMetadata> getCatalogMetadata(ImageEntry entry, {bool background = false}) async {
     if (entry.isSvg) return null;
 
-    final call = () async {
+    Future<CatalogMetadata> call() async {
       try {
         // return map with:
         // 'mimeType': MIME type as reported by metadata extractors, not Media Store (string)
@@ -47,7 +47,7 @@ class MetadataService {
         debugPrint('getCatalogMetadata failed with code=${e.code}, exception=${e.message}, details=${e.details}');
       }
       return null;
-    };
+    }
     return background
         ? servicePolicy.call(
             call,

lib/utils/color_utils.dart

@@ -5,7 +5,7 @@ final Map<String, Color> _stringColors = {};
 Color stringToColor(String string, {double saturation = .8, double lightness = .6}) {
   var color = _stringColors[string];
   if (color == null) {
-    final hash = string.codeUnits.fold(0, (prev, el) => prev = el + ((prev << 5) - prev));
+    final hash = string.codeUnits.fold<int>(0, (prev, el) => prev = el + ((prev << 5) - prev));
     final hue = (hash % 360).toDouble();
     color = HSLColor.fromAHSL(1.0, hue, saturation, lightness).toColor();
     _stringColors[string] = color;

lib/utils/durations.dart

@@ -30,5 +30,5 @@ class Durations {
   static const collectionScrollMonitoringTimerDelay = Duration(milliseconds: 100);
   static const collectionScalingCompleteNotificationDelay = Duration(milliseconds: 300);
   static const videoProgressTimerInterval = Duration(milliseconds: 300);
-  static var staggeredAnimationDelay = Durations.staggeredAnimation ~/ 6 * timeDilation;
+  static Duration staggeredAnimationDelay = Durations.staggeredAnimation ~/ 6 * timeDilation;
 }

lib/utils/time_utils.dart

@@ -20,7 +20,7 @@ extension ExtraDateTime on DateTime {
 
   bool get isToday => isAtSameDayAs(DateTime.now());
 
-  bool get isYesterday => isAtSameDayAs(DateTime.now().subtract(const Duration(days: 1)));
+  bool get isYesterday => isAtSameDayAs(DateTime.now().subtract(Duration(days: 1)));
 
   bool get isThisMonth => isAtSameMonthAs(DateTime.now());
 

lib/widgets/about/about_page.dart

@@ -11,20 +11,20 @@ class AboutPage extends StatelessWidget {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: const Text('About'),
+        title: Text('About'),
       ),
       body: SafeArea(
         child: AnimationLimiter(
           child: CustomScrollView(
             slivers: [
               SliverPadding(
-                padding: const EdgeInsets.only(top: 16),
+                padding: EdgeInsets.only(top: 16),
                 sliver: SliverList(
                   delegate: SliverChildListDelegate(
                     [
                       AppReference(),
-                      const SizedBox(height: 16),
-                      const Divider(),
+                      SizedBox(height: 16),
+                      Divider(),
                     ],
                   ),
                 ),
@@ -92,7 +92,7 @@ class _AppReferenceState extends State<AppReference> {
         children: [
           WidgetSpan(
             child: Padding(
-              padding: const EdgeInsetsDirectional.only(end: 4),
+              padding: EdgeInsetsDirectional.only(end: 4),
               child: FlutterLogo(
                 size: style.fontSize * 1.25,
               ),

lib/widgets/about/licenses.dart

@@ -39,7 +39,7 @@ class _LicensesState extends State<Licenses> {
   @override
   Widget build(BuildContext context) {
     return SliverPadding(
-      padding: const EdgeInsets.symmetric(horizontal: 8),
+      padding: EdgeInsets.symmetric(horizontal: 8),
       sliver: SliverList(
         delegate: SliverChildBuilderDelegate(
           (context, index) {
@@ -69,7 +69,7 @@ class _LicensesState extends State<Licenses> {
     return Column(
       children: [
         Padding(
-          padding: const EdgeInsetsDirectional.only(start: 8),
+          padding: EdgeInsetsDirectional.only(start: 8),
           child: Row(
             children: [
               Expanded(
@@ -95,13 +95,13 @@ class _LicensesState extends State<Licenses> {
                   setState(() {});
                 },
                 tooltip: 'Sort',
-                icon: const Icon(AIcons.sort),
+                icon: Icon(AIcons.sort),
               ),
             ],
           ),
         ),
-        const SizedBox(height: 8),
-        const Padding(
+        SizedBox(height: 8),
+        Padding(
           padding: EdgeInsets.symmetric(horizontal: 8),
           child: Text('The following sets forth attribution notices for third party software that may be contained in this application.'),
         ),
@@ -122,17 +122,17 @@ class LicenseRow extends StatelessWidget {
     final subColor = bodyTextStyle.color.withOpacity(.6);
 
     return Padding(
-      padding: const EdgeInsets.only(top: 16),
+      padding: EdgeInsets.only(top: 16),
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
           LinkChip(
             text: package.name,
             url: package.sourceUrl,
-            textStyle: const TextStyle(fontWeight: FontWeight.bold),
+            textStyle: TextStyle(fontWeight: FontWeight.bold),
           ),
           Padding(
-            padding: const EdgeInsetsDirectional.only(start: 16),
+            padding: EdgeInsetsDirectional.only(start: 16),
             child: LinkChip(
               text: package.license,
               url: package.licenseUrl,

lib/widgets/album/app_bar.dart

@@ -144,7 +144,7 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
         // so that we can also detect taps around the title `Text`
         child: Container(
           alignment: AlignmentDirectional.centerStart,
-          padding: const EdgeInsets.symmetric(horizontal: NavigationToolbar.kMiddleSpacing),
+          padding: EdgeInsets.symmetric(horizontal: NavigationToolbar.kMiddleSpacing),
           color: Colors.transparent,
           height: kToolbarHeight,
           child: title,
@@ -155,7 +155,7 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
         animation: collection.selectionChangeNotifier,
         builder: (context, child) {
           final count = collection.selection.length;
-          return Text(Intl.plural(count, zero: 'Select items', one: '${count} item', other: '${count} items'));
+          return Text(Intl.plural(count, zero: 'Select items', one: '$count item', other: '$count items'));
         },
       );
     }
@@ -166,7 +166,7 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
     return [
       if (collection.isBrowsing)
         IconButton(
-          icon: const Icon(AIcons.search),
+          icon: Icon(AIcons.search),
           onPressed: _goToSearch,
         ),
       if (collection.isSelecting)
@@ -190,15 +190,15 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
               if (collection.isBrowsing) ...[
                 if (AvesApp.mode == AppMode.main)
                   if (kDebugMode)
-                    const PopupMenuItem(
+                    PopupMenuItem(
                       value: CollectionAction.refresh,
                       child: MenuRow(text: 'Refresh', icon: AIcons.refresh),
                     ),
-                const PopupMenuItem(
+                PopupMenuItem(
                   value: CollectionAction.select,
                   child: MenuRow(text: 'Select', icon: AIcons.select),
                 ),
-                const PopupMenuItem(
+                PopupMenuItem(
                   value: CollectionAction.stats,
                   child: MenuRow(text: 'Stats', icon: AIcons.stats),
                 ),
@@ -207,27 +207,27 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
                 PopupMenuItem(
                   value: CollectionAction.copy,
                   enabled: hasSelection,
-                  child: const MenuRow(text: 'Copy to album'),
+                  child: MenuRow(text: 'Copy to album'),
                 ),
                 PopupMenuItem(
                   value: CollectionAction.move,
                   enabled: hasSelection,
-                  child: const MenuRow(text: 'Move to album'),
+                  child: MenuRow(text: 'Move to album'),
                 ),
                 PopupMenuItem(
                   value: CollectionAction.refreshMetadata,
                   enabled: hasSelection,
-                  child: const MenuRow(text: 'Refresh metadata'),
+                  child: MenuRow(text: 'Refresh metadata'),
                 ),
-                const PopupMenuDivider(),
-                const PopupMenuItem(
+                PopupMenuDivider(),
+                PopupMenuItem(
                   value: CollectionAction.selectAll,
                   child: MenuRow(text: 'Select all'),
                 ),
                 PopupMenuItem(
                   value: CollectionAction.selectNone,
                   enabled: hasSelection,
-                  child: const MenuRow(text: 'Select none'),
+                  child: MenuRow(text: 'Select none'),
                 ),
               ]
             ];
@@ -252,7 +252,7 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
         value: CollectionAction.sortByName,
         child: MenuRow(text: 'Sort by name', checked: collection.sortFactor == SortFactor.name),
       ),
-      const PopupMenuDivider(),
+      PopupMenuDivider(),
     ];
   }
 
@@ -271,7 +271,7 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
               value: CollectionAction.groupByDay,
               child: MenuRow(text: 'Group by day', checked: collection.groupFactor == GroupFactor.day),
             ),
-            const PopupMenuDivider(),
+            PopupMenuDivider(),
           ]
         : [];
   }

lib/widgets/album/empty.dart

@@ -24,10 +24,10 @@ class EmptyContent extends StatelessWidget {
             size: 64,
             color: color,
           ),
-          const SizedBox(height: 16),
+          SizedBox(height: 16),
           Text(
             text,
-            style: const TextStyle(
+            style: TextStyle(
               color: color,
               fontSize: 22,
               fontFamily: 'Concourse',

lib/widgets/album/filter_bar.dart

@@ -18,7 +18,7 @@ class FilterBar extends StatefulWidget implements PreferredSizeWidget {
         super(key: key);
 
   @override
-  final Size preferredSize = const Size.fromHeight(preferredHeight);
+  final Size preferredSize = Size.fromHeight(preferredHeight);
 
   @override
   _FilterBarState createState() => _FilterBarState();
@@ -85,8 +85,8 @@ class _FilterBarState extends State<FilterBar> {
           key: _animatedListKey,
           initialItemCount: widget.filters.length,
           scrollDirection: Axis.horizontal,
-          physics: const BouncingScrollPhysics(),
-          padding: const EdgeInsets.only(left: 8),
+          physics: BouncingScrollPhysics(),
+          padding: EdgeInsets.only(left: 8),
           itemBuilder: (context, index, animation) {
             if (index >= widget.filters.length) return null;
             return _buildChip(widget.filters.toList()[index]);
@@ -98,7 +98,7 @@ class _FilterBarState extends State<FilterBar> {
 
   Padding _buildChip(CollectionFilter filter) {
     return Padding(
-      padding: const EdgeInsets.only(right: 8),
+      padding: EdgeInsets.only(right: 8),
       child: Center(
         child: AvesFilterChip(
           key: ValueKey(filter),

lib/widgets/album/grid/header_album.dart

@@ -29,7 +29,7 @@ class AlbumSectionHeader extends StatelessWidget {
       leading: albumIcon,
       title: albumName,
       trailing: androidFileUtils.isOnRemovableStorage(folderPath)
-          ? const Icon(
+          ? Icon(
               AIcons.removableStorage,
               size: 16,
               color: Color(0xFF757575),

lib/widgets/album/grid/header_generic.dart

@@ -54,7 +54,7 @@ class SectionHeader extends StatelessWidget {
             height: height,
             child: header,
           )
-        : const SizedBox.shrink();
+        : SizedBox.shrink();
   }
 
   Widget _buildAlbumSectionHeader() {
@@ -128,7 +128,9 @@ class TitleSectionHeader extends StatelessWidget {
     return Container(
       alignment: AlignmentDirectional.centerStart,
       padding: padding,
-      constraints: const BoxConstraints(minHeight: leadingDimension),
+      constraints: BoxConstraints(minHeight: leadingDimension),
+      child: GestureDetector(
+        onTap: () => _toggleSectionSelection(context),
         child: Text.rich(
           TextSpan(
             children: [
@@ -144,6 +146,7 @@ class TitleSectionHeader extends StatelessWidget {
                             child: leading,
                           )
                       : null,
+                  onPressed: () => _toggleSectionSelection(context),
                 ),
               ),
               TextSpan(
@@ -161,18 +164,32 @@ class TitleSectionHeader extends StatelessWidget {
             ],
           ),
         ),
+      ),
     );
   }
+
+  void _toggleSectionSelection(BuildContext context) {
+    final collection = Provider.of<CollectionLens>(context, listen: false);
+    final sectionEntries = collection.sections[sectionKey];
+    final selected = collection.isSelected(sectionEntries);
+    if (selected) {
+      collection.removeFromSelection(sectionEntries);
+    } else {
+      collection.addToSelection(sectionEntries);
+    }
+  }
 }
 
 class SectionSelectableLeading extends StatelessWidget {
   final dynamic sectionKey;
   final WidgetBuilder browsingBuilder;
+  final VoidCallback onPressed;
 
   const SectionSelectableLeading({
     Key key,
     @required this.sectionKey,
     @required this.browsingBuilder,
+    @required this.onPressed,
   }) : super(key: key);
 
   static const leadingDimension = TitleSectionHeader.leadingDimension;
@@ -196,18 +213,12 @@ class SectionSelectableLeading extends StatelessWidget {
                     ),
                     child: IconButton(
                       iconSize: 26,
-                      padding: const EdgeInsets.only(top: 1),
+                      padding: EdgeInsets.only(top: 1),
                       alignment: Alignment.topLeft,
                       icon: Icon(selected ? AIcons.selected : AIcons.unselected),
-                      onPressed: () {
-                        if (selected) {
-                          collection.removeFromSelection(sectionEntries);
-                        } else {
-                          collection.addToSelection(sectionEntries);
-                        }
-                      },
+                      onPressed: onPressed,
                       tooltip: selected ? 'Deselect section' : 'Select section',
-                      constraints: const BoxConstraints(
+                      constraints: BoxConstraints(
                         minHeight: leadingDimension,
                         minWidth: leadingDimension,
                       ),
@@ -225,7 +236,7 @@ class SectionSelectableLeading extends StatelessWidget {
                   );
                 },
               )
-            : browsingBuilder?.call(context) ?? const SizedBox(height: leadingDimension);
+            : browsingBuilder?.call(context) ?? SizedBox(height: leadingDimension);
         return AnimatedSwitcher(
           duration: Durations.sectionHeaderAnimation,
           switchInCurve: Curves.easeInOut,

lib/widgets/album/grid/list_section_layout.dart

@@ -4,7 +4,6 @@ import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/widgets/album/grid/header_generic.dart';
 import 'package:aves/widgets/album/grid/tile_extent_manager.dart';
-import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
@@ -110,7 +109,7 @@ class SectionedListLayoutProvider extends StatelessWidget {
             sectionKey: sectionKey,
             height: headerExtent,
           )
-        : const SizedBox.shrink();
+        : SizedBox.shrink();
   }
 }
 
@@ -145,25 +144,6 @@ class SectionedListLayout {
     final top = sectionLayout.indexToLayoutOffset(listIndex);
     return Rect.fromLTWH(left, top, tileExtent, tileExtent);
   }
-
-  int rowIndex(dynamic sectionKey, List<int> builtIds) {
-    if (!collection.sections.containsKey(sectionKey)) return null;
-
-    final section = collection.sections[sectionKey];
-    final firstId = builtIds.first;
-    final firstIndexInSection = section.indexWhere((entry) => entry.contentId == firstId);
-    if (firstIndexInSection % columnCount != 0) return null;
-
-    final collectionIds = section.skip(firstIndexInSection).take(builtIds.length).map((entry) => entry.contentId);
-    final eq = const IterableEquality().equals;
-    if (eq(builtIds, collectionIds)) {
-      final sectionLayout = sectionLayouts.firstWhere((section) => section.sectionKey == sectionKey, orElse: () => null);
-      if (sectionLayout == null) return null;
-      return sectionLayout.firstIndex + 1 + firstIndexInSection ~/ columnCount;
-    }
-
-    return null;
-  }
 }
 
 class SectionLayout {

lib/widgets/album/grid/list_sliver.dart

@@ -26,7 +26,7 @@ class CollectionListSliver extends StatelessWidget {
         (context, index) {
           if (index >= childCount) return null;
           final sectionLayout = sectionLayouts.firstWhere((section) => section.hasChild(index), orElse: () => null);
-          return sectionLayout?.builder(context, index) ?? const SizedBox.shrink();
+          return sectionLayout?.builder(context, index) ?? SizedBox.shrink();
         },
         childCount: childCount,
         addAutomaticKeepAlives: false,

lib/widgets/album/grid/scaling.dart

@@ -62,7 +62,7 @@ class _GridScaleGestureDetectorState extends State<GridScaleGestureDetector> {
         scrollableBox.hitTest(result, position: details.localFocalPoint);
 
         // find `RenderObject`s at the gesture focal point
-        final firstOf = <T>(BoxHitTestResult result) => result.path.firstWhere((el) => el.target is T, orElse: () => null)?.target as T;
+        T firstOf<T>(BoxHitTestResult result) => result.path.firstWhere((el) => el.target is T, orElse: () => null)?.target as T;
         final renderMetaData = firstOf<RenderMetaData>(result);
         // abort if we cannot find an image to show on overlay
         if (renderMetaData == null) return;
@@ -192,7 +192,7 @@ class _ScaleOverlayState extends State<ScaleOverlay> {
                     ],
                   ),
                 )
-              : const BoxDecoration(
+              : BoxDecoration(
                   // provide dummy gradient to lerp to the other one during animation
                   gradient: RadialGradient(
                     colors: [

lib/widgets/album/search/expandable_filter_row.dart

@@ -23,7 +23,7 @@ class ExpandableFilterRow extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    if (filters.isEmpty) return const SizedBox.shrink();
+    if (filters.isEmpty) return SizedBox.shrink();
 
     final hasTitle = title != null && title.isNotEmpty;
 
@@ -32,7 +32,7 @@ class ExpandableFilterRow extends StatelessWidget {
     Widget titleRow;
     if (hasTitle) {
       titleRow = Padding(
-        padding: const EdgeInsets.all(16),
+        padding: EdgeInsets.all(16),
         child: Row(
           children: [
             Text(
@@ -52,7 +52,7 @@ class ExpandableFilterRow extends StatelessWidget {
     final filtersList = filters.toList();
     final wrap = Container(
       key: ValueKey('wrap$title'),
-      padding: const EdgeInsets.symmetric(horizontal: horizontalPadding),
+      padding: EdgeInsets.symmetric(horizontal: horizontalPadding),
       // specify transparent as a workaround to prevent
       // chip border clipping when the floating app bar is fading
       color: Colors.transparent,
@@ -75,8 +75,8 @@ class ExpandableFilterRow extends StatelessWidget {
       height: AvesFilterChip.minChipHeight,
       child: ListView.separated(
         scrollDirection: Axis.horizontal,
-        physics: const BouncingScrollPhysics(),
-        padding: const EdgeInsets.symmetric(horizontal: horizontalPadding),
+        physics: BouncingScrollPhysics(),
+        padding: EdgeInsets.symmetric(horizontal: horizontalPadding),
         itemBuilder: (context, index) {
           if (index >= filtersList.length) return null;
           final filter = filtersList[index];
@@ -85,7 +85,7 @@ class ExpandableFilterRow extends StatelessWidget {
             onPressed: onPressed,
           );
         },
-        separatorBuilder: (context, index) => const SizedBox(width: 8),
+        separatorBuilder: (context, index) => SizedBox(width: 8),
         itemCount: filtersList.length,
       ),
     );

lib/widgets/album/search/search_delegate.dart

@@ -44,7 +44,7 @@ class ImageSearchDelegate extends SearchDelegate<CollectionFilter> {
     return [
       if (query.isNotEmpty)
         IconButton(
-          icon: const Icon(AIcons.clear),
+          icon: Icon(AIcons.clear),
           onPressed: () {
             query = '';
             showSuggestions(context);
@@ -57,23 +57,23 @@ class ImageSearchDelegate extends SearchDelegate<CollectionFilter> {
   @override
   Widget buildSuggestions(BuildContext context) {
     final upQuery = query.trim().toUpperCase();
-    final containQuery = (String s) => s.toUpperCase().contains(upQuery);
+    bool containQuery(String s) => s.toUpperCase().contains(upQuery);
     return SafeArea(
       child: ValueListenableBuilder<String>(
           valueListenable: expandedSectionNotifier,
           builder: (context, expandedSection, child) {
             return ListView(
-              padding: const EdgeInsets.only(top: 8),
+              padding: EdgeInsets.only(top: 8),
               children: [
                 _buildFilterRow(
                   context: context,
                   filters: [
                     _buildQueryFilter(false),
                     FavouriteFilter(),
-                    MimeFilter(MimeTypes.ANY_IMAGE),
-                    MimeFilter(MimeTypes.ANY_VIDEO),
+                    MimeFilter(MimeTypes.anyImage),
+                    MimeFilter(MimeTypes.anyVideo),
                     MimeFilter(MimeFilter.animated),
-                    MimeFilter(MimeTypes.SVG),
+                    MimeFilter(MimeTypes.svg),
                   ].where((f) => f != null && containQuery(f.label)),
                 ),
                 StreamBuilder(
@@ -135,7 +135,7 @@ class ImageSearchDelegate extends SearchDelegate<CollectionFilter> {
       // and possibly trigger a rebuild here
       _select(context, _buildQueryFilter(true));
     });
-    return const SizedBox.shrink();
+    return SizedBox.shrink();
   }
 
   QueryFilter _buildQueryFilter(bool colorful) {

lib/widgets/album/thumbnail/overlay.dart

@@ -57,7 +57,7 @@ class ThumbnailSelectionOverlay extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final duration = Durations.thumbnailOverlayAnimation;
+    const duration = Durations.thumbnailOverlayAnimation;
     final fontSize = min(14.0, (extent / 8)).roundToDouble();
     final iconSize = fontSize * 2;
     final collection = Provider.of<CollectionLens>(context);
@@ -75,7 +75,7 @@ class ThumbnailSelectionOverlay extends StatelessWidget {
                           icon: selected ? AIcons.selected : AIcons.unselected,
                           size: iconSize,
                         )
-                      : const SizedBox.shrink();
+                      : SizedBox.shrink();
                   child = AnimatedSwitcher(
                     duration: duration,
                     switchInCurve: Curves.easeOutBack,
@@ -95,7 +95,7 @@ class ThumbnailSelectionOverlay extends StatelessWidget {
                   return child;
                 },
               )
-            : const SizedBox.shrink();
+            : SizedBox.shrink();
         return AnimatedSwitcher(
           duration: duration,
           child: child,

lib/widgets/album/thumbnail/raster.dart

@@ -81,7 +81,7 @@ class _ThumbnailRasterImageState extends State<ThumbnailRasterImage> {
   @override
   Widget build(BuildContext context) {
     final fastImage = Image(
-      key: const ValueKey('LQ'),
+      key: ValueKey('LQ'),
       image: _fastThumbnailProvider,
       width: extent,
       height: extent,
@@ -90,7 +90,7 @@ class _ThumbnailRasterImageState extends State<ThumbnailRasterImage> {
     final image = _sizedThumbnailProvider == null
         ? fastImage
         : Image(
-            key: const ValueKey('HQ'),
+            key: ValueKey('HQ'),
             frameBuilder: (context, child, frame, wasSynchronouslyLoaded) {
               if (wasSynchronouslyLoaded) return child;
               return AnimatedSwitcher(

lib/widgets/album/thumbnail_collection.dart

@@ -36,7 +36,7 @@ class ThumbnailCollection extends StatelessWidget {
           final mqSize = mq.item1;
           final mqHorizontalPadding = mq.item2;
 
-          if (mqSize.isEmpty) return const SizedBox.shrink();
+          if (mqSize.isEmpty) return SizedBox.shrink();
 
           TileExtentManager.applyTileExtent(mqSize, mqHorizontalPadding, _tileExtentNotifier);
           final cacheExtent = TileExtentManager.extentMaxForSize(mqSize) * 2;
@@ -159,7 +159,7 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
       primary: true,
       // workaround to prevent scrolling the app bar away
       // when there is no content and we use `SliverFillRemaining`
-      physics: collection.isEmpty ? const NeverScrollableScrollPhysics() : const SloppyScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
+      physics: collection.isEmpty ? NeverScrollableScrollPhysics() : SloppyScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
       cacheExtent: widget.cacheExtent,
       slivers: [
         appBar,
@@ -168,7 +168,7 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
                 child: _buildEmptyCollectionPlaceholder(collection),
                 hasScrollBody: false,
               )
-            : const CollectionListSliver(),
+            : CollectionListSliver(),
         SliverToBoxAdapter(
           child: Selector<MediaQueryData, double>(
             selector: (context, mq) => mq.viewInsets.bottom,
@@ -211,22 +211,22 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
       valueListenable: collection.source.stateNotifier,
       builder: (context, sourceState, child) {
         if (sourceState == SourceState.loading) {
-          return const SizedBox.shrink();
+          return SizedBox.shrink();
         }
         if (collection.filters.any((filter) => filter is FavouriteFilter)) {
-          return const EmptyContent(
+          return EmptyContent(
             icon: AIcons.favourite,
             text: 'No favourites',
           );
         }
         debugPrint('collection.filters=${collection.filters}');
-        if (collection.filters.any((filter) => filter is MimeFilter && filter.mime == MimeTypes.ANY_VIDEO)) {
-          return const EmptyContent(
+        if (collection.filters.any((filter) => filter is MimeFilter && filter.mime == MimeTypes.anyVideo)) {
+          return EmptyContent(
             icon: AIcons.video,
             text: 'No videos',
           );
         }
-        return const EmptyContent(
+        return EmptyContent(
           icon: AIcons.image,
           text: 'No images',
         );

lib/widgets/app_drawer.dart

@@ -46,7 +46,7 @@ class _AppDrawerState extends State<AppDrawer> {
         ),
       ),
       child: Container(
-        padding: const EdgeInsets.all(16),
+        padding: EdgeInsets.all(16),
         color: Theme.of(context).accentColor,
         child: SafeArea(
           child: Column(
@@ -58,8 +58,8 @@ class _AppDrawerState extends State<AppDrawer> {
                   spacing: 16,
                   crossAxisAlignment: WrapCrossAlignment.center,
                   children: [
-                    const AvesLogo(size: 64),
-                    const Text(
+                    AvesLogo(size: 64),
+                    Text(
                       'Aves',
                       style: TextStyle(
                         fontSize: 44,
@@ -77,19 +77,19 @@ class _AppDrawerState extends State<AppDrawer> {
 
     final allMediaEntry = _FilteredCollectionNavTile(
       source: source,
-      leading: const Icon(AIcons.allMedia),
+      leading: Icon(AIcons.allMedia),
       title: 'All media',
       filter: null,
     );
     final videoEntry = _FilteredCollectionNavTile(
       source: source,
-      leading: const Icon(AIcons.video),
+      leading: Icon(AIcons.video),
       title: 'Videos',
-      filter: MimeFilter(MimeTypes.ANY_VIDEO),
+      filter: MimeFilter(MimeTypes.anyVideo),
     );
     final favouriteEntry = _FilteredCollectionNavTile(
       source: source,
-      leading: const Icon(AIcons.favourite),
+      leading: Icon(AIcons.favourite),
       title: 'Favourites',
       filter: FavouriteFilter(),
     );
@@ -97,8 +97,8 @@ class _AppDrawerState extends State<AppDrawer> {
       top: false,
       bottom: false,
       child: ListTile(
-        leading: const Icon(AIcons.info),
-        title: const Text('About'),
+        leading: Icon(AIcons.info),
+        title: Text('About'),
         onTap: () => _goToAbout(context),
       ),
     );
@@ -109,20 +109,20 @@ class _AppDrawerState extends State<AppDrawer> {
       videoEntry,
       favouriteEntry,
       _buildSpecialAlbumSection(),
-      const Divider(),
+      Divider(),
       _buildRegularAlbumSection(),
       _buildCountrySection(),
       _buildTagSection(),
-      const Divider(),
+      Divider(),
       aboutEntry,
       if (kDebugMode) ...[
-        const Divider(),
+        Divider(),
         SafeArea(
           top: false,
           bottom: false,
           child: ListTile(
-            leading: const Icon(AIcons.debug),
-            title: const Text('Debug'),
+            leading: Icon(AIcons.debug),
+            title: Text('Debug'),
             onTap: () => _goToDebug(context),
           ),
         ),
@@ -157,7 +157,7 @@ class _AppDrawerState extends State<AppDrawer> {
       leading: IconUtils.getAlbumIcon(context: context, album: album),
       title: uniqueName,
       trailing: androidFileUtils.isOnRemovableStorage(album)
-          ? const Icon(
+          ? Icon(
               AIcons.removableStorage,
               size: 16,
               color: Colors.grey,
@@ -177,10 +177,10 @@ class _AppDrawerState extends State<AppDrawer> {
             return type != AlbumType.regular && type != AlbumType.app;
           });
 
-          if (specialAlbums.isEmpty) return const SizedBox.shrink();
+          if (specialAlbums.isEmpty) return SizedBox.shrink();
           return Column(
             children: [
-              const Divider(),
+              Divider(),
               ...specialAlbums.map((album) => _buildAlbumEntry(album, dense: false)),
             ],
           );
@@ -192,8 +192,8 @@ class _AppDrawerState extends State<AppDrawer> {
       top: false,
       bottom: false,
       child: ListTile(
-        leading: const Icon(AIcons.album),
-        title: const Text('Albums'),
+        leading: Icon(AIcons.album),
+        title: Text('Albums'),
         trailing: StreamBuilder(
             stream: source.eventBus.on<AlbumsChangedEvent>(),
             builder: (context, snapshot) {
@@ -214,8 +214,8 @@ class _AppDrawerState extends State<AppDrawer> {
       top: false,
       bottom: false,
       child: ListTile(
-        leading: const Icon(AIcons.location),
-        title: const Text('Countries'),
+        leading: Icon(AIcons.location),
+        title: Text('Countries'),
         trailing: StreamBuilder(
             stream: source.eventBus.on<LocationsChangedEvent>(),
             builder: (context, snapshot) {
@@ -236,8 +236,8 @@ class _AppDrawerState extends State<AppDrawer> {
       top: false,
       bottom: false,
       child: ListTile(
-        leading: const Icon(AIcons.tag),
-        title: const Text('Tags'),
+        leading: Icon(AIcons.tag),
+        title: Text('Tags'),
         trailing: StreamBuilder(
             stream: source.eventBus.on<TagsChangedEvent>(),
             builder: (context, snapshot) {
@@ -263,7 +263,7 @@ class _AppDrawerState extends State<AppDrawer> {
           title: 'Albums',
           filterEntries: source.getAlbumEntries(),
           filterBuilder: (s) => AlbumFilter(s, source.getUniqueAlbumName(s)),
-          emptyBuilder: () => const EmptyContent(
+          emptyBuilder: () => EmptyContent(
             icon: AIcons.album,
             text: 'No albums',
           ),
@@ -282,7 +282,7 @@ class _AppDrawerState extends State<AppDrawer> {
           title: 'Countries',
           filterEntries: source.getCountryEntries(),
           filterBuilder: (s) => LocationFilter(LocationLevel.country, s),
-          emptyBuilder: () => const EmptyContent(
+          emptyBuilder: () => EmptyContent(
             icon: AIcons.location,
             text: 'No countries',
           ),
@@ -301,7 +301,7 @@ class _AppDrawerState extends State<AppDrawer> {
           title: 'Tags',
           filterEntries: source.getTagEntries(),
           filterBuilder: (s) => TagFilter(s),
-          emptyBuilder: () => const EmptyContent(
+          emptyBuilder: () => EmptyContent(
             icon: AIcons.tag,
             text: 'No tags',
           ),

lib/widgets/common/action_delegates/create_album_dialog.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+
 import 'package:aves/utils/android_file_utils.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
@@ -10,19 +12,17 @@ class CreateAlbumDialog extends StatefulWidget {
 
 class _CreateAlbumDialogState extends State<CreateAlbumDialog> {
   final TextEditingController _nameController = TextEditingController();
-  Set<StorageVolume> allVolumes;
-  StorageVolume primaryVolume, selectedVolume;
+  final ValueNotifier<bool> _existsNotifier = ValueNotifier(false);
+  Set<StorageVolume> _allVolumes;
+  StorageVolume _primaryVolume, _selectedVolume;
 
   @override
   void initState() {
     super.initState();
-
-    // TODO TLAD improve new album default name
-    _nameController.text = 'Album 1';
-
-    allVolumes = androidFileUtils.storageVolumes;
-    primaryVolume = allVolumes.firstWhere((volume) => volume.isPrimary, orElse: () => allVolumes.first);
-    selectedVolume = primaryVolume;
+    _allVolumes = androidFileUtils.storageVolumes;
+    _primaryVolume = _allVolumes.firstWhere((volume) => volume.isPrimary, orElse: () => _allVolumes.first);
+    _selectedVolume = _primaryVolume;
+    _initAlbumName();
   }
 
   @override
@@ -34,20 +34,20 @@ class _CreateAlbumDialogState extends State<CreateAlbumDialog> {
   @override
   Widget build(BuildContext context) {
     return AlertDialog(
-      title: const Text('New Album'),
+      title: Text('New Album'),
       content: Column(
         mainAxisSize: MainAxisSize.min,
         children: [
-          if (allVolumes.length > 1) ...[
+          if (_allVolumes.length > 1) ...[
             Row(
               mainAxisSize: MainAxisSize.min,
               children: [
-                const Text('Storage:'),
-                const SizedBox(width: 8),
+                Text('Storage:'),
+                SizedBox(width: 8),
                 Expanded(
                   child: DropdownButton<StorageVolume>(
                     isExpanded: true,
-                    items: allVolumes
+                    items: _allVolumes
                         .map((volume) => DropdownMenuItem(
                               value: volume,
                               child: Text(
@@ -58,37 +58,67 @@ class _CreateAlbumDialogState extends State<CreateAlbumDialog> {
                               ),
                             ))
                         .toList(),
-                    value: selectedVolume,
-                    onChanged: (volume) => setState(() => selectedVolume = volume),
+                    value: _selectedVolume,
+                    onChanged: (volume) {
+                      _selectedVolume = volume;
+                      _checkAlbumExists();
+                      setState(() {});
+                    },
                   ),
                 ),
               ],
             ),
-            const SizedBox(height: 16),
+            SizedBox(height: 16),
           ],
-          TextField(
+          ValueListenableBuilder<bool>(
+              valueListenable: _existsNotifier,
+              builder: (context, exists, child) {
+                return TextField(
                   controller: _nameController,
-//            autofocus: true,
+                  decoration: InputDecoration(
+                    helperText: exists ? 'Album already exists' : '',
                   ),
+                  onChanged: (_) => _checkAlbumExists(),
+                  onSubmitted: (_) => _submit(context),
+                );
+              }),
         ],
       ),
-      contentPadding: const EdgeInsets.fromLTRB(24, 20, 24, 0),
+      contentPadding: EdgeInsets.fromLTRB(24, 20, 24, 0),
       actions: [
         FlatButton(
           onPressed: () => Navigator.pop(context),
           child: Text('Cancel'.toUpperCase()),
         ),
         FlatButton(
-          onPressed: () => Navigator.pop(context, _buildAlbumPath()),
+          onPressed: () => _submit(context),
           child: Text('Create'.toUpperCase()),
         ),
       ],
     );
   }
 
-  String _buildAlbumPath() {
-    final newName = _nameController.text;
-    if (newName == null || newName.isEmpty) return null;
-    return join(selectedVolume == primaryVolume ? androidFileUtils.dcimPath : selectedVolume.path, newName);
+  String _buildAlbumPath(String name) {
+    if (name == null || name.isEmpty) return '';
+    return join(_selectedVolume.path, 'Pictures', name);
+  }
+
+  Future<void> _initAlbumName() async {
+    var count = 1;
+    while (true) {
+      var name = 'Album $count';
+      if (!await Directory(_buildAlbumPath(name)).exists()) {
+        _nameController.text = name;
+        return;
+      }
+      count++;
     }
   }
+
+  Future<void> _checkAlbumExists() async {
+    final path = _buildAlbumPath(_nameController.text);
+    _existsNotifier.value = path.isEmpty ? false : await Directory(path).exists();
+  }
+
+  void _submit(BuildContext context) => Navigator.pop(context, _buildAlbumPath(_nameController.text));
+}

lib/widgets/common/action_delegates/entry_action_delegate.dart

@@ -118,9 +118,9 @@ class EntryActionDelegate with FeedbackMixin, PermissionAwareMixin {
   Future<void> _showDeleteDialog(BuildContext context, ImageEntry entry) async {
     final confirmed = await showDialog<bool>(
       context: context,
-      builder: (BuildContext context) {
+      builder: (context) {
         return AlertDialog(
-          content: const Text('Are you sure?'),
+          content: Text('Are you sure?'),
           actions: [
             FlatButton(
               onPressed: () => Navigator.pop(context),

lib/widgets/common/action_delegates/feedback.dart

@@ -11,7 +11,7 @@ mixin FeedbackMixin {
   void showFeedback(BuildContext context, String message) {
     _flushbar = Flushbar(
       message: message,
-      margin: const EdgeInsets.all(8),
+      margin: EdgeInsets.all(8),
       borderRadius: 8,
       borderColor: Colors.white30,
       borderWidth: 0.5,

lib/widgets/common/action_delegates/permission_aware.dart

@@ -1,34 +1,30 @@
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/services/android_file_service.dart';
-import 'package:aves/utils/android_file_utils.dart';
 import 'package:flutter/material.dart';
-import 'package:tuple/tuple.dart';
 
 mixin PermissionAwareMixin {
   Future<bool> checkStoragePermission(BuildContext context, Iterable<ImageEntry> entries) {
-    return checkStoragePermissionForPaths(context, entries.where((e) => e.path != null).map((e) => e.path));
+    return checkStoragePermissionForAlbums(context, entries.where((e) => e.path != null).map((e) => e.directory).toSet());
   }
 
-  Future<bool> checkStoragePermissionForPaths(BuildContext context, Iterable<String> paths) async {
-    final volumes = paths.map(androidFileUtils.getStorageVolume).toSet();
-    final ungrantedVolumes = (await Future.wait<Tuple2<StorageVolume, bool>>(
-      volumes.map(
-        (volume) => AndroidFileService.requireVolumeAccessDialog(volume.path).then(
-          (granted) => Tuple2(volume, granted),
-        ),
-      ),
-    ))
-        .where((t) => t.item2)
-        .map((t) => t.item1)
-        .toList();
-    while (ungrantedVolumes.isNotEmpty) {
-      final volume = ungrantedVolumes.first;
+  Future<bool> checkStoragePermissionForAlbums(BuildContext context, Set<String> albumPaths) async {
+    while (true) {
+      final dirs = await AndroidFileService.getInaccessibleDirectories(albumPaths);
+      if (dirs == null) return false;
+      if (dirs.isEmpty) return true;
+
+      final dir = dirs.first;
+      final volumePath = dir['volumePath'] as String;
+      final volumeDescription = dir['volumeDescription'] as String;
+      final relativeDir = dir['relativeDir'] as String;
+      final dirDisplayName = relativeDir.isEmpty ? 'root' : '“$relativeDir”';
+
       final confirmed = await showDialog<bool>(
         context: context,
-        builder: (BuildContext context) {
+        builder: (context) {
           return AlertDialog(
-            title: const Text('Storage Volume Access'),
-            content: Text('Please select the root directory of “${volume.description}” in the next screen, so that this app can access it and complete your request.'),
+            title: Text('Storage Volume Access'),
+            content: Text('Please select the $dirDisplayName directory of “$volumeDescription” in the next screen, so that this app can access it and complete your request.'),
             actions: [
               FlatButton(
                 onPressed: () => Navigator.pop(context),
@@ -45,15 +41,11 @@ mixin PermissionAwareMixin {
       // abort if the user cancels in Flutter
       if (confirmed == null || !confirmed) return false;
 
-      final granted = await AndroidFileService.requestVolumeAccess(volume.path);
-      debugPrint('$runtimeType _checkStoragePermission with volume=${volume.path} got granted=$granted');
-      if (granted) {
-        ungrantedVolumes.remove(volume);
-      } else {
+      final granted = await AndroidFileService.requestVolumeAccess(volumePath);
+      if (!granted) {
         // abort if the user denies access from the native dialog
         return false;
       }
     }
-    return true;
   }
 }

lib/widgets/common/action_delegates/selection_action_delegate.dart

@@ -69,7 +69,7 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
           return FilterGridPage(
             source: source,
             appBar: SliverAppBar(
-              leading: const BackButton(),
+              leading: BackButton(),
               title: Text(copy ? 'Copy to Album' : 'Move to Album'),
               actions: [
                 IconButton(
@@ -90,7 +90,7 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
             ),
             filterEntries: source.getAlbumEntries(),
             filterBuilder: (s) => AlbumFilter(s, source.getUniqueAlbumName(s)),
-            emptyBuilder: () => const EmptyContent(
+            emptyBuilder: () => EmptyContent(
               icon: AIcons.album,
               text: 'No albums',
             ),
@@ -100,26 +100,26 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
       ),
     );
     if (destinationAlbum == null || destinationAlbum.isEmpty) return;
-    if (!await checkStoragePermissionForPaths(context, [destinationAlbum])) return;
+    if (!await checkStoragePermissionForAlbums(context, {destinationAlbum})) return;
 
     final selection = collection.selection.toList();
     if (!await checkStoragePermission(context, selection)) return;
 
-    _showOpReport(
+    _showOpReport<MoveOpEvent>(
       context: context,
       selection: selection,
       opStream: ImageFileService.move(selection, copy: copy, destinationAlbum: destinationAlbum),
-      onDone: (Set<MoveOpEvent> processed) async {
+      onDone: (processed) async {
         debugPrint('$runtimeType _moveSelection onDone');
         final movedOps = processed.where((e) => e.success);
         final movedCount = movedOps.length;
         final selectionCount = selection.length;
         if (movedCount < selectionCount) {
           final count = selectionCount - movedCount;
-          showFeedback(context, 'Failed to move ${Intl.plural(count, one: '${count} item', other: '${count} items')}');
+          showFeedback(context, 'Failed to move ${Intl.plural(count, one: '$count item', other: '$count items')}');
         } else {
           final count = movedCount;
-          showFeedback(context, '${copy ? 'Copied' : 'Moved'} ${Intl.plural(count, one: '${count} item', other: '${count} items')}');
+          showFeedback(context, '${copy ? 'Copied' : 'Moved'} ${Intl.plural(count, one: '$count item', other: '$count items')}');
         }
         if (movedCount > 0) {
           final fromAlbums = <String>{};
@@ -187,9 +187,9 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
 
     final confirmed = await showDialog<bool>(
       context: context,
-      builder: (BuildContext context) {
+      builder: (context) {
         return AlertDialog(
-          content: Text('Are you sure you want to delete ${Intl.plural(count, one: 'this item', other: 'these ${count} items')}?'),
+          content: Text('Are you sure you want to delete ${Intl.plural(count, one: 'this item', other: 'these $count items')}?'),
           actions: [
             FlatButton(
               onPressed: () => Navigator.pop(context),
@@ -207,17 +207,17 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
 
     if (!await checkStoragePermission(context, selection)) return;
 
-    _showOpReport(
+    _showOpReport<ImageOpEvent>(
       context: context,
       selection: selection,
       opStream: ImageFileService.delete(selection),
-      onDone: (Set<ImageOpEvent> processed) {
+      onDone: (processed) {
         final deletedUris = processed.where((e) => e.success).map((e) => e.uri);
         final deletedCount = deletedUris.length;
         final selectionCount = selection.length;
         if (deletedCount < selectionCount) {
           final count = selectionCount - deletedCount;
-          showFeedback(context, 'Failed to delete ${Intl.plural(count, one: '${count} item', other: '${count} items')}');
+          showFeedback(context, 'Failed to delete ${Intl.plural(count, one: '$count item', other: '$count items')}');
         }
         if (deletedCount > 0) {
           collection.source.removeEntries(selection.where((e) => deletedUris.contains(e.uri)));
@@ -242,9 +242,9 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
 
     // do not handle completion inside `StreamBuilder`
     // as it could be called multiple times
-    final onComplete = () => _hideOpReportOverlay().then((_) => onDone(processed));
+    Future<void> onComplete() => _hideOpReportOverlay().then((_) => onDone(processed));
     opStream.listen(
-      (event) => processed.add(event),
+      processed.add,
       onError: (error) {
         debugPrint('_showOpReport error=$error');
         onComplete();
@@ -258,7 +258,7 @@ class SelectionActionDelegate with FeedbackMixin, PermissionAwareMixin {
           child: StreamBuilder<T>(
               stream: opStream,
               builder: (context, snapshot) {
-                Widget child = const SizedBox.shrink();
+                Widget child = SizedBox.shrink();
                 if (!snapshot.hasError && snapshot.connectionState == ConnectionState.active) {
                   final percent = processed.length.toDouble() / selection.length;
                   child = CircularPercentIndicator(

lib/widgets/common/app_bar_subtitle.dart

@@ -32,7 +32,7 @@ class SourceStateAwareAppBarTitle extends StatelessWidget {
                 ),
               ),
               child: sourceState == SourceState.ready
-                  ? const SizedBox.shrink()
+                  ? SizedBox.shrink()
                   : SourceStateSubtitle(
                       source: source,
                     ),
@@ -68,7 +68,7 @@ class SourceStateSubtitle extends StatelessWidget {
     }
     final subtitleStyle = Theme.of(context).textTheme.caption;
     return subtitle == null
-        ? const SizedBox.shrink()
+        ? SizedBox.shrink()
         : Row(
             mainAxisSize: MainAxisSize.min,
             children: [
@@ -76,10 +76,10 @@ class SourceStateSubtitle extends StatelessWidget {
               StreamBuilder<ProgressEvent>(
                 stream: source.progressStream,
                 builder: (context, snapshot) {
-            if (snapshot.hasError || !snapshot.hasData) return const SizedBox.shrink();
+                  if (snapshot.hasError || !snapshot.hasData) return SizedBox.shrink();
                   final progress = snapshot.data;
                   return Padding(
-              padding: const EdgeInsetsDirectional.only(start: 8),
+                    padding: EdgeInsetsDirectional.only(start: 8),
                     child: Text(
                       '${progress.done}/${progress.total}',
                       style: subtitleStyle.copyWith(color: Colors.white30),

lib/widgets/common/aves_filter_chip.dart

@@ -66,7 +66,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
   Widget build(BuildContext context) {
     final hasBackground = widget.background != null;
     final leading = filter.iconBuilder(context, AvesFilterChip.iconSize, showGenericIcon: widget.showGenericIcon);
-    final trailing = widget.removable ? const Icon(AIcons.clear, size: AvesFilterChip.iconSize) : null;
+    final trailing = widget.removable ? Icon(AIcons.clear, size: AvesFilterChip.iconSize) : null;
 
     Widget content = Row(
       mainAxisSize: hasBackground ? MainAxisSize.max : MainAxisSize.min,
@@ -74,7 +74,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
       children: [
         if (leading != null) ...[
           leading,
-          const SizedBox(width: AvesFilterChip.padding),
+          SizedBox(width: AvesFilterChip.padding),
         ],
         Flexible(
           child: Text(
@@ -85,7 +85,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
           ),
         ),
         if (trailing != null) ...[
-          const SizedBox(width: AvesFilterChip.padding),
+          SizedBox(width: AvesFilterChip.padding),
           trailing,
         ],
       ],
@@ -102,7 +102,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
     }
 
     content = Padding(
-      padding: const EdgeInsets.symmetric(horizontal: AvesFilterChip.padding * 2, vertical: 2),
+      padding: EdgeInsets.symmetric(horizontal: AvesFilterChip.padding * 2, vertical: 2),
       child: content,
     );
 
@@ -112,7 +112,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
           color: Colors.black54,
           child: DefaultTextStyle(
             style: Theme.of(context).textTheme.bodyText2.copyWith(
-              shadows: const [
+              shadows: [
                 Shadow(
                   color: Colors.black87,
                   offset: Offset(0.5, 1.0),
@@ -128,7 +128,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
     final borderRadius = AvesFilterChip.borderRadius;
 
     Widget chip = Container(
-      constraints: const BoxConstraints(
+      constraints: BoxConstraints(
         minWidth: AvesFilterChip.minChipWidth,
         maxWidth: AvesFilterChip.maxChipWidth,
         minHeight: AvesFilterChip.minChipHeight,
@@ -157,9 +157,9 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
                       }
                     : null,
                 borderRadius: borderRadius,
-                child: FutureBuilder(
+                child: FutureBuilder<Color>(
                   future: _colorFuture,
-                  builder: (context, AsyncSnapshot<Color> snapshot) {
+                  builder: (context, snapshot) {
                     final outlineColor = snapshot.hasData ? snapshot.data : Colors.transparent;
                     return DecoratedBox(
                       decoration: BoxDecoration(
@@ -171,7 +171,7 @@ class _AvesFilterChipState extends State<AvesFilterChip> {
                       ),
                       position: DecorationPosition.foreground,
                       child: Padding(
-                        padding: const EdgeInsets.symmetric(vertical: 8),
+                        padding: EdgeInsets.symmetric(vertical: 8),
                         child: content,
                       ),
                     );

lib/widgets/common/data_providers/media_store_collection_provider.dart

@@ -51,11 +51,11 @@ class MediaStoreSource extends CollectionSource {
     var refreshCount = 10;
     const refreshCountMax = 1000;
     final allNewEntries = <ImageEntry>[], pendingNewEntries = <ImageEntry>[];
-    final addPendingEntries = () {
+    void addPendingEntries() {
       allNewEntries.addAll(pendingNewEntries);
       addAll(pendingNewEntries);
       pendingNewEntries.clear();
-    };
+    }
     ImageFileService.getImageEntries(knownEntryMap).listen(
       (entry) {
         pendingNewEntries.add(entry);

lib/widgets/common/icons.dart

@@ -131,10 +131,10 @@ class OverlayIcon extends StatelessWidget {
     );
 
     return Container(
-      margin: const EdgeInsets.all(1),
+      margin: EdgeInsets.all(1),
       padding: text != null ? EdgeInsets.only(right: size / 4) : null,
       decoration: BoxDecoration(
-        color: const Color(0xBB000000),
+        color: Color(0xBB000000),
         borderRadius: BorderRadius.all(
           Radius.circular(size),
         ),
@@ -146,7 +146,7 @@ class OverlayIcon extends StatelessWidget {
               crossAxisAlignment: CrossAxisAlignment.center,
               children: [
                 iconChild,
-                const SizedBox(width: 2),
+                SizedBox(width: 2),
                 Text(text),
               ],
             ),

lib/widgets/common/image_providers/thumbnail_provider.dart

@@ -54,7 +54,7 @@ class ThumbnailProvider extends ImageProvider<ThumbnailProviderKey> {
   }
 
   @override
-  void resolveStreamForKey(ImageConfiguration configuration, ImageStream stream, ThumbnailProviderKey key, handleError) {
+  void resolveStreamForKey(ImageConfiguration configuration, ImageStream stream, ThumbnailProviderKey key, ImageErrorListener handleError) {
     ImageFileService.resumeThumbnail(_cancellationKey);
     super.resolveStreamForKey(configuration, stream, key, handleError);
   }

lib/widgets/common/link_chip.dart

@@ -23,7 +23,7 @@ class LinkChip extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return DefaultTextStyle.merge(
-      style: (textStyle ?? const TextStyle()).copyWith(color: color),
+      style: (textStyle ?? TextStyle()).copyWith(color: color),
       child: InkWell(
         borderRadius: borderRadius,
         onTap: () async {
@@ -32,16 +32,16 @@ class LinkChip extends StatelessWidget {
           }
         },
         child: Padding(
-          padding: const EdgeInsets.all(8.0),
+          padding: EdgeInsets.all(8.0),
           child: Row(
             mainAxisSize: MainAxisSize.min,
             children: [
               if (leading != null) ...[
                 leading,
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
               ],
               Text(text),
-              const SizedBox(width: 8),
+              SizedBox(width: 8),
               Builder(
                 builder: (context) => Icon(
                   AIcons.openInNew,

lib/widgets/common/menu_row.dart

@@ -20,13 +20,13 @@ class MenuRow extends StatelessWidget {
         if (checked != null) ...[
           Opacity(
             opacity: checked ? 1 : 0,
-            child: const Icon(AIcons.checked),
+            child: Icon(AIcons.checked),
           ),
-          const SizedBox(width: 8),
+          SizedBox(width: 8),
         ],
         if (icon != null) ...[
           Icon(icon),
-          const SizedBox(width: 8),
+          SizedBox(width: 8),
         ],
         Expanded(child: Text(text)),
       ],

lib/widgets/common/scroll_thumb.dart

@@ -10,21 +10,21 @@ ScrollThumbBuilder avesScrollThumbBuilder({
   @required Color backgroundColor,
 }) {
   final scrollThumb = Container(
-    decoration: const BoxDecoration(
+    decoration: BoxDecoration(
       color: Colors.black26,
       borderRadius: BorderRadius.all(
         Radius.circular(12.0),
       ),
     ),
     height: height,
-    margin: const EdgeInsets.only(right: .5),
-    padding: const EdgeInsets.all(2),
+    margin: EdgeInsets.only(right: .5),
+    padding: EdgeInsets.all(2),
     child: ClipPath(
       child: Container(
         width: 20.0,
         decoration: BoxDecoration(
           color: backgroundColor,
-          borderRadius: const BorderRadius.all(
+          borderRadius: BorderRadius.all(
             Radius.circular(12.0),
           ),
         ),
@@ -32,13 +32,7 @@ ScrollThumbBuilder avesScrollThumbBuilder({
       clipper: ArrowClipper(),
     ),
   );
-  return (
-    Color backgroundColor,
-    Animation<double> thumbAnimation,
-    Animation<double> labelAnimation,
-    double height, {
-    Widget labelText,
-  }) {
+  return (backgroundColor, thumbAnimation, labelAnimation, height, {labelText}) {
     return DraggableScrollbar.buildScrollThumbAndLabel(
       scrollThumb: scrollThumb,
       backgroundColor: backgroundColor,

lib/widgets/common/transition_image.dart

@@ -12,7 +12,7 @@ class TransitionImage extends StatefulWidget {
   final ImageProvider image;
   final double width, height;
   final ValueListenable<double> animation;
-  final gaplessPlayback = false;
+  final bool gaplessPlayback = false;
 
   const TransitionImage({
     @required this.image,

lib/widgets/debug_page.dart

@@ -7,7 +7,6 @@ import 'package:aves/model/metadata_db.dart';
 import 'package:aves/model/settings.dart';
 import 'package:aves/model/source/collection_source.dart';
 import 'package:aves/services/android_app_service.dart';
-import 'package:aves/services/android_file_service.dart';
 import 'package:aves/services/image_file_service.dart';
 import 'package:aves/utils/android_file_utils.dart';
 import 'package:aves/utils/file_utils.dart';
@@ -17,7 +16,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:outline_material_icons/outline_material_icons.dart';
-import 'package:tuple/tuple.dart';
 
 class DebugPage extends StatefulWidget {
   final CollectionSource source;
@@ -35,7 +33,6 @@ class DebugPageState extends State<DebugPage> {
   Future<List<CatalogMetadata>> _dbMetadataLoader;
   Future<List<AddressDetails>> _dbAddressLoader;
   Future<List<FavouriteRow>> _dbFavouritesLoader;
-  Future<List<Tuple2<String, bool>>> _volumePermissionLoader;
   Future<Map> _envLoader;
 
   List<ImageEntry> get entries => widget.source.rawEntries;
@@ -44,13 +41,6 @@ class DebugPageState extends State<DebugPage> {
   void initState() {
     super.initState();
     _startDbReport();
-    _volumePermissionLoader = Future.wait<Tuple2<String, bool>>(
-      androidFileUtils.storageVolumes.map(
-        (volume) => AndroidFileService.requireVolumeAccessDialog(volume.path).then(
-          (value) => Tuple2(volume.path, !value),
-        ),
-      ),
-    );
     _envLoader = AndroidAppService.getEnv();
   }
 
@@ -61,8 +51,8 @@ class DebugPageState extends State<DebugPage> {
         length: 4,
         child: Scaffold(
           appBar: AppBar(
-            title: const Text('Debug'),
-            bottom: const TabBar(
+            title: Text('Debug'),
+            bottom: TabBar(
               tabs: [
                 Tab(icon: Icon(OMIcons.whatshot)),
                 Tab(icon: Icon(OMIcons.settings)),
@@ -91,9 +81,9 @@ class DebugPageState extends State<DebugPage> {
     final withGps = catalogued.where((entry) => entry.hasGps);
     final located = withGps.where((entry) => entry.isLocated);
     return ListView(
-      padding: const EdgeInsets.all(16),
+      padding: EdgeInsets.all(16),
       children: [
-        const Text('Time dilation'),
+        Text('Time dilation'),
         Slider(
           value: timeDilation,
           onChanged: (v) => setState(() => timeDilation = v),
@@ -102,24 +92,24 @@ class DebugPageState extends State<DebugPage> {
           divisions: 9,
           label: '$timeDilation',
         ),
-        const Divider(),
+        Divider(),
         Text('Entries: ${entries.length}'),
         Text('Catalogued: ${catalogued.length}'),
         Text('With GPS: ${withGps.length}'),
         Text('With address: ${located.length}'),
-        const Divider(),
+        Divider(),
         Row(
           children: [
             Expanded(
               child: Text('Image cache:\n\t${imageCache.currentSize}/${imageCache.maximumSize} items\n\t${formatFilesize(imageCache.currentSizeBytes)}/${formatFilesize(imageCache.maximumSizeBytes)}'),
             ),
-            const SizedBox(width: 8),
+            SizedBox(width: 8),
             RaisedButton(
               onPressed: () {
                 imageCache.clear();
                 setState(() {});
               },
-              child: const Text('Clear'),
+              child: Text('Clear'),
             ),
           ],
         ),
@@ -128,138 +118,138 @@ class DebugPageState extends State<DebugPage> {
             Expanded(
               child: Text('SVG cache: ${PictureProvider.cacheCount} items'),
             ),
-            const SizedBox(width: 8),
+            SizedBox(width: 8),
             RaisedButton(
               onPressed: () {
                 PictureProvider.clearCache();
                 setState(() {});
               },
-              child: const Text('Clear'),
+              child: Text('Clear'),
             ),
           ],
         ),
         Row(
           children: [
-            const Expanded(
+            Expanded(
               child: Text('Glide disk cache: ?'),
             ),
-            const SizedBox(width: 8),
+            SizedBox(width: 8),
             RaisedButton(
-              onPressed: () => ImageFileService.clearSizedThumbnailDiskCache(),
-              child: const Text('Clear'),
+              onPressed: ImageFileService.clearSizedThumbnailDiskCache,
+              child: Text('Clear'),
             ),
           ],
         ),
-        const Divider(),
-        FutureBuilder(
+        Divider(),
+        FutureBuilder<int>(
           future: _dbFileSizeLoader,
-          builder: (context, AsyncSnapshot<int> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB file size: ${formatFilesize(snapshot.data)}'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => metadataDb.reset().then((_) => _startDbReport()),
-                  child: const Text('Reset'),
+                  child: Text('Reset'),
                 ),
               ],
             );
           },
         ),
-        FutureBuilder(
+        FutureBuilder<List>(
           future: _dbEntryLoader,
-          builder: (context, AsyncSnapshot<List> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB entry rows: ${snapshot.data.length}'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => metadataDb.clearEntries().then((_) => _startDbReport()),
-                  child: const Text('Clear'),
+                  child: Text('Clear'),
                 ),
               ],
             );
           },
         ),
-        FutureBuilder(
+        FutureBuilder<List>(
           future: _dbDateLoader,
-          builder: (context, AsyncSnapshot<List> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB date rows: ${snapshot.data.length}'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => metadataDb.clearDates().then((_) => _startDbReport()),
-                  child: const Text('Clear'),
+                  child: Text('Clear'),
                 ),
               ],
             );
           },
         ),
-        FutureBuilder(
+        FutureBuilder<List>(
           future: _dbMetadataLoader,
-          builder: (context, AsyncSnapshot<List> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB metadata rows: ${snapshot.data.length}'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => metadataDb.clearMetadataEntries().then((_) => _startDbReport()),
-                  child: const Text('Clear'),
+                  child: Text('Clear'),
                 ),
               ],
             );
           },
         ),
-        FutureBuilder(
+        FutureBuilder<List>(
           future: _dbAddressLoader,
-          builder: (context, AsyncSnapshot<List> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB address rows: ${snapshot.data.length}'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => metadataDb.clearAddresses().then((_) => _startDbReport()),
-                  child: const Text('Clear'),
+                  child: Text('Clear'),
                 ),
               ],
             );
           },
         ),
-        FutureBuilder(
+        FutureBuilder<List>(
           future: _dbFavouritesLoader,
-          builder: (context, AsyncSnapshot<List> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             return Row(
               children: [
                 Expanded(
                   child: Text('DB favourite rows: ${snapshot.data.length} (${favourites.count} in memory)'),
                 ),
-                const SizedBox(width: 8),
+                SizedBox(width: 8),
                 RaisedButton(
                   onPressed: () => favourites.clear().then((_) => _startDbReport()),
-                  child: const Text('Clear'),
+                  child: Text('Clear'),
                 ),
               ],
             );
@@ -271,17 +261,17 @@ class DebugPageState extends State<DebugPage> {
 
   Widget _buildSettingsTabView() {
     return ListView(
-      padding: const EdgeInsets.all(16),
+      padding: EdgeInsets.all(16),
       children: [
         Row(
           children: [
-            const Expanded(
+            Expanded(
               child: Text('Settings'),
             ),
-            const SizedBox(width: 8),
+            SizedBox(width: 8),
             RaisedButton(
               onPressed: () => settings.reset().then((_) => setState(() {})),
-              child: const Text('Reset'),
+              child: Text('Reset'),
             ),
           ],
         ),
@@ -297,16 +287,7 @@ class DebugPageState extends State<DebugPage> {
 
   Widget _buildStorageTabView() {
     return ListView(
-      padding: const EdgeInsets.all(16),
-      children: [
-        FutureBuilder(
-          future: _volumePermissionLoader,
-          builder: (context, AsyncSnapshot<List<Tuple2<String, bool>>> snapshot) {
-            if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
-            final permissions = snapshot.data;
-            return Column(
-              crossAxisAlignment: CrossAxisAlignment.start,
+      padding: EdgeInsets.all(16),
       children: [
         ...androidFileUtils.storageVolumes.expand((v) => [
               Text(v.path),
@@ -316,27 +297,22 @@ class DebugPageState extends State<DebugPage> {
                 'isPrimary': '${v.isPrimary}',
                 'isRemovable': '${v.isRemovable}',
                 'state': '${v.state}',
-                        'permission': '${permissions.firstWhere((t) => t.item1 == v.path, orElse: () => null)?.item2 ?? false}',
               }),
-                      const Divider(),
+              Divider(),
             ])
       ],
     );
-          },
-        ),
-      ],
-    );
   }
 
   Widget _buildEnvTabView() {
     return ListView(
-      padding: const EdgeInsets.all(16),
+      padding: EdgeInsets.all(16),
       children: [
-        FutureBuilder(
+        FutureBuilder<Map>(
           future: _envLoader,
-          builder: (context, AsyncSnapshot<Map> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             final data = SplayTreeMap.of(snapshot.data.map((k, v) => MapEntry(k.toString(), v?.toString() ?? 'null')));
             return InfoRowGroup(data);
           },

lib/widgets/filter_grid_page.dart

@@ -106,7 +106,7 @@ class FilterGridPage extends StatelessWidget {
                             hasScrollBody: false,
                           )
                         : SliverPadding(
-                            padding: const EdgeInsets.all(AvesFilterChip.outlineWidth),
+                            padding: EdgeInsets.all(AvesFilterChip.outlineWidth),
                             sliver: SliverGrid(
                               delegate: SliverChildBuilderDelegate(
                                 (context, i) {
@@ -132,7 +132,7 @@ class FilterGridPage extends StatelessWidget {
                                 },
                                 childCount: filterKeys.length,
                               ),
-                              gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
+                              gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
                                 maxCrossAxisExtent: maxCrossAxisExtent,
                                 mainAxisSpacing: 8,
                                 crossAxisSpacing: 8,
@@ -201,18 +201,18 @@ class DecoratedFilterChip extends StatelessWidget {
   Widget _buildDetails(CollectionFilter filter) {
     final count = Text(
       '${source.count(filter)}',
-      style: const TextStyle(color: FilterGridPage.detailColor),
+      style: TextStyle(color: FilterGridPage.detailColor),
     );
     return filter is AlbumFilter && androidFileUtils.isOnRemovableStorage(filter.album)
         ? Row(
             mainAxisSize: MainAxisSize.min,
             children: [
-              const Icon(
+              Icon(
                 AIcons.removableStorage,
                 size: 16,
                 color: FilterGridPage.detailColor,
               ),
-              const SizedBox(width: 8),
+              SizedBox(width: 8),
               count,
             ],
           )

lib/widgets/fullscreen/debug.dart

@@ -1,4 +1,5 @@
 import 'dart:collection';
+import 'dart:typed_data';
 
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/image_metadata.dart';
@@ -36,8 +37,8 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
       length: 2,
       child: Scaffold(
         appBar: AppBar(
-          title: const Text('Debug'),
-          bottom: const TabBar(
+          title: Text('Debug'),
+          bottom: TabBar(
             tabs: [
               Tab(text: 'DB'),
               Tab(text: 'Content Resolver'),
@@ -59,13 +60,13 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
   Widget _buildDbTabView() {
     final catalog = widget.entry.catalogMetadata;
     return ListView(
-      padding: const EdgeInsets.all(16),
+      padding: EdgeInsets.all(16),
       children: [
-        FutureBuilder(
+        FutureBuilder<DateMetadata>(
           future: _dbDateLoader,
-          builder: (context, AsyncSnapshot<DateMetadata> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             final data = snapshot.data;
             return Column(
               crossAxisAlignment: CrossAxisAlignment.start,
@@ -79,12 +80,12 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
             );
           },
         ),
-        const SizedBox(height: 16),
-        FutureBuilder(
+        SizedBox(height: 16),
+        FutureBuilder<CatalogMetadata>(
           future: _dbMetadataLoader,
-          builder: (context, AsyncSnapshot<CatalogMetadata> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             final data = snapshot.data;
             return Column(
               crossAxisAlignment: CrossAxisAlignment.start,
@@ -105,12 +106,12 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
             );
           },
         ),
-        const SizedBox(height: 16),
-        FutureBuilder(
+        SizedBox(height: 16),
+        FutureBuilder<AddressDetails>(
           future: _dbAddressLoader,
-          builder: (context, AsyncSnapshot<AddressDetails> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             final data = snapshot.data;
             return Column(
               crossAxisAlignment: CrossAxisAlignment.start,
@@ -128,7 +129,7 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
             );
           },
         ),
-        const Divider(),
+        Divider(),
         Text('Catalog metadata:${catalog == null ? ' no data' : ''}'),
         if (catalog != null)
           InfoRowGroup({
@@ -152,13 +153,13 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
 
   Widget _buildContentResolverTabView() {
     return ListView(
-      padding: const EdgeInsets.all(16),
+      padding: EdgeInsets.all(16),
       children: [
-        FutureBuilder(
+        FutureBuilder<Map>(
           future: _contentResolverMetadataLoader,
-          builder: (context, AsyncSnapshot<Map> snapshot) {
+          builder: (context, snapshot) {
             if (snapshot.hasError) return Text(snapshot.error.toString());
-            if (snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+            if (snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
             final data = SplayTreeMap.of(snapshot.data.map((k, v) {
               final key = k.toString();
               var value = v?.toString() ?? 'null';
@@ -168,6 +169,9 @@ class _FullscreenDebugPageState extends State<FullscreenDebugPage> {
                 }
                 value += ' (${DateTime.fromMillisecondsSinceEpoch(v)})';
               }
+              if (key == 'xmp' && v != null && v is Uint8List) {
+                value = String.fromCharCodes(v);
+              }
               return MapEntry(key, value);
             }));
             return InfoRowGroup(data);

lib/widgets/fullscreen/fullscreen_body.dart

@@ -87,7 +87,7 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
       // no bounce at the bottom, to avoid video controller displacement
       curve: Curves.easeOutQuad,
     );
-    _bottomOverlayOffset = Tween(begin: const Offset(0, 1), end: const Offset(0, 0)).animate(CurvedAnimation(
+    _bottomOverlayOffset = Tween(begin: Offset(0, 1), end: Offset(0, 0)).animate(CurvedAnimation(
       parent: _overlayAnimationController,
       curve: Curves.easeOutQuad,
     ));
@@ -178,7 +178,7 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
     final child = ValueListenableBuilder<ImageEntry>(
       valueListenable: _entryNotifier,
       builder: (context, entry, child) {
-        if (entry == null) return const SizedBox.shrink();
+        if (entry == null) return SizedBox.shrink();
         return FullscreenTopOverlay(
           entry: entry,
           scale: _topOverlayScale,
@@ -459,7 +459,7 @@ class _FullscreenVerticalPageViewState extends State<FullscreenVerticalPageView>
   Widget build(BuildContext context) {
     final pages = [
       // fake page for opacity transition between collection and fullscreen views
-      const SizedBox(),
+      SizedBox(),
       hasCollection
           ? MultiImagePage(
               collection: collection,
@@ -494,7 +494,7 @@ class _FullscreenVerticalPageViewState extends State<FullscreenVerticalPageView>
       child: PageView(
         scrollDirection: Axis.vertical,
         controller: widget.verticalPager,
-        physics: const PhotoViewPageViewScrollPhysics(parent: PageScrollPhysics()),
+        physics: PhotoViewPageViewScrollPhysics(parent: PageScrollPhysics()),
         onPageChanged: (page) {
           widget.onVerticalPageChanged(page);
           _infoPageVisibleNotifier.value = page == pages.length - 1;

lib/widgets/fullscreen/image_page.dart

@@ -39,7 +39,7 @@ class MultiImagePageState extends State<MultiImagePage> with AutomaticKeepAliveC
       child: PageView.builder(
         scrollDirection: Axis.horizontal,
         controller: widget.pageController,
-        physics: const PhotoViewPageViewScrollPhysics(parent: BouncingScrollPhysics()),
+        physics: PhotoViewPageViewScrollPhysics(parent: BouncingScrollPhysics()),
         onPageChanged: widget.onPageChanged,
         itemBuilder: (context, index) {
           final entry = entries[index];

lib/widgets/fullscreen/image_view.dart

@@ -41,7 +41,7 @@ class ImageView extends StatelessWidget {
                 entry: entry,
                 controller: videoController,
               )
-            : const SizedBox(),
+            : SizedBox(),
         backgroundDecoration: backgroundDecoration,
         scaleStateChangedCallback: onScaleChanged,
         minScale: PhotoViewComputedScale.contained,
@@ -61,7 +61,7 @@ class ImageView extends StatelessWidget {
     // if the image is already in the cache it will show the final image, otherwise the thumbnail
     // in any case, we should use `Center` + `AspectRatio` + `Fill` so that the transition image
     // appears as the final image with `PhotoViewComputedScale.contained` for `initialScale`
-    final loadingBuilder = (BuildContext context, ImageProvider imageProvider) {
+    Widget loadingBuilder(BuildContext context, ImageProvider imageProvider) {
       return Center(
         child: AspectRatio(
           // enforce original aspect ratio, as some thumbnails aspect ratios slightly differ
@@ -72,7 +72,7 @@ class ImageView extends StatelessWidget {
           ),
         ),
       );
-    };
+    }
 
     Widget child;
     if (entry.isSvg) {
@@ -107,7 +107,7 @@ class ImageView extends StatelessWidget {
           context,
           imageCache.statusForKey(uriImage).keepAlive ? uriImage : fastThumbnailProvider,
         ),
-        loadFailedChild: const EmptyContent(
+        loadFailedChild: EmptyContent(
           icon: AIcons.error,
           text: 'Oops!',
           alignment: Alignment.center,

lib/widgets/fullscreen/info/basic_section.dart

@@ -53,7 +53,7 @@ class BasicSection extends StatelessWidget {
     final tags = entry.xmpSubjects..sort(compareAsciiUpperCase);
     final album = entry.directory;
     final filters = [
-      if (entry.isVideo) MimeFilter(MimeTypes.ANY_VIDEO),
+      if (entry.isVideo) MimeFilter(MimeTypes.anyVideo),
       if (entry.isAnimated) MimeFilter(MimeFilter.animated),
       if (album != null) AlbumFilter(album, collection?.source?.getUniqueAlbumName(album)),
       ...tags.map((tag) => TagFilter(tag)),
@@ -65,9 +65,9 @@ class BasicSection extends StatelessWidget {
           ...filters,
           if (entry.isFavourite) FavouriteFilter(),
         ]..sort();
-        if (effectiveFilters.isEmpty) return const SizedBox.shrink();
+        if (effectiveFilters.isEmpty) return SizedBox.shrink();
         return Padding(
-          padding: const EdgeInsets.symmetric(horizontal: AvesFilterChip.outlineWidth / 2) + const EdgeInsets.only(top: 8),
+          padding: EdgeInsets.symmetric(horizontal: AvesFilterChip.outlineWidth / 2) + EdgeInsets.only(top: 8),
           child: Wrap(
             spacing: 8,
             runSpacing: 8,

lib/widgets/fullscreen/info/info_page.dart

@@ -40,11 +40,11 @@ class InfoPageState extends State<InfoPage> {
 
     final appBar = SliverAppBar(
       leading: IconButton(
-        icon: const Icon(AIcons.goUp),
+        icon: Icon(AIcons.goUp),
         onPressed: _goToImage,
         tooltip: 'Back to image',
       ),
-      title: const Text('Info'),
+      title: Text('Info'),
       floating: true,
     );
 
@@ -60,7 +60,7 @@ class InfoPageState extends State<InfoPage> {
                 final mqViewInsetsBottom = mq.item2;
                 final split = mqWidth > 400;
 
-                return ValueListenableBuilder(
+                return ValueListenableBuilder<ImageEntry>(
                   valueListenable: widget.entryNotifier,
                   builder: (context, entry, child) {
                     final locationAtTop = split && entry.hasGps;
@@ -77,7 +77,7 @@ class InfoPageState extends State<InfoPage> {
                               crossAxisAlignment: CrossAxisAlignment.start,
                               children: [
                                 Expanded(child: BasicSection(entry: entry, collection: collection, onFilter: _goToCollection)),
-                                const SizedBox(width: 8),
+                                SizedBox(width: 8),
                                 Expanded(child: locationSection),
                               ],
                             ),
@@ -100,7 +100,7 @@ class InfoPageState extends State<InfoPage> {
                       slivers: [
                         appBar,
                         SliverPadding(
-                          padding: horizontalPadding + const EdgeInsets.only(top: 8),
+                          padding: horizontalPadding + EdgeInsets.only(top: 8),
                           sliver: basicAndLocationSliver,
                         ),
                         SliverPadding(
@@ -165,7 +165,7 @@ class SectionRow extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     const dim = 32.0;
-    final buildDivider = () => const SizedBox(
+    Widget buildDivider() => SizedBox(
           width: dim,
           child: Divider(
             thickness: AvesFilterChip.outlineWidth,
@@ -177,7 +177,7 @@ class SectionRow extends StatelessWidget {
       children: [
         buildDivider(),
         Padding(
-          padding: const EdgeInsets.all(16.0),
+          padding: EdgeInsets.all(16.0),
           child: Icon(
             icon,
             size: dim,
@@ -196,7 +196,7 @@ class InfoRowGroup extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    if (keyValues.isEmpty) return const SizedBox.shrink();
+    if (keyValues.isEmpty) return SizedBox.shrink();
     final lastKey = keyValues.keys.last;
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
@@ -206,13 +206,13 @@ class InfoRowGroup extends StatelessWidget {
             children: keyValues.entries
                 .expand(
                   (kv) => [
-                    TextSpan(text: '${kv.key}     ', style: const TextStyle(color: Colors.white70, height: 1.7)),
+                    TextSpan(text: '${kv.key}     ', style: TextStyle(color: Colors.white70, height: 1.7)),
                     TextSpan(text: '${kv.value}${kv.key == lastKey ? '' : '\n'}'),
                   ],
                 )
                 .toList(),
           ),
-          style: const TextStyle(fontFamily: 'Concourse'),
+          style: TextStyle(fontFamily: 'Concourse'),
         ),
       ],
     );

lib/widgets/fullscreen/info/location_section.dart

@@ -1,7 +1,7 @@
-import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/model/filters/location.dart';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/settings.dart';
+import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/services/android_app_service.dart';
 import 'package:aves/utils/geo_utils.dart';
 import 'package:aves/widgets/common/aves_filter_chip.dart';
@@ -90,7 +90,7 @@ class _LocationSectionState extends State<LocationSection> {
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
           if (widget.showTitle)
-            const Padding(
+            Padding(
               padding: EdgeInsets.only(bottom: 8),
               child: SectionRow(AIcons.location),
             ),
@@ -105,12 +105,12 @@ class _LocationSectionState extends State<LocationSection> {
           ),
           if (location.isNotEmpty)
             Padding(
-              padding: const EdgeInsets.only(top: 8),
+              padding: EdgeInsets.only(top: 8),
               child: InfoRowGroup({'Address': location}),
             ),
           if (filters.isNotEmpty)
             Padding(
-              padding: const EdgeInsets.symmetric(horizontal: AvesFilterChip.outlineWidth / 2) + const EdgeInsets.only(top: 8),
+              padding: EdgeInsets.symmetric(horizontal: AvesFilterChip.outlineWidth / 2) + EdgeInsets.only(top: 8),
               child: Wrap(
                 spacing: 8,
                 runSpacing: 8,
@@ -126,7 +126,7 @@ class _LocationSectionState extends State<LocationSection> {
       );
     } else {
       _loadedUri = null;
-      return const SizedBox.shrink();
+      return SizedBox.shrink();
     }
   }
 
@@ -175,7 +175,7 @@ class ImageMapState extends State<ImageMap> with AutomaticKeepAliveClientMixin {
               // and triggering by mistake a move to the image page above
             },
             child: ClipRRect(
-              borderRadius: const BorderRadius.all(
+              borderRadius: BorderRadius.all(
                 Radius.circular(16),
               ),
               child: Container(
@@ -208,24 +208,24 @@ class ImageMapState extends State<ImageMap> with AutomaticKeepAliveClientMixin {
             ),
           ),
         ),
-        const SizedBox(width: 8),
+        SizedBox(width: 8),
         TooltipTheme(
           data: TooltipTheme.of(context).copyWith(
             preferBelow: false,
           ),
           child: Column(children: [
             IconButton(
-              icon: const Icon(AIcons.zoomIn),
+              icon: Icon(AIcons.zoomIn),
               onPressed: _controller == null ? null : () => _zoomBy(1),
               tooltip: 'Zoom in',
             ),
             IconButton(
-              icon: const Icon(AIcons.zoomOut),
+              icon: Icon(AIcons.zoomOut),
               onPressed: _controller == null ? null : () => _zoomBy(-1),
               tooltip: 'Zoom out',
             ),
             IconButton(
-              icon: const Icon(AIcons.openInNew),
+              icon: Icon(AIcons.openInNew),
               onPressed: () => AndroidAppService.openMap(widget.geoUri),
               tooltip: 'Show on map...',
             ),

lib/widgets/fullscreen/info/metadata_section.dart

@@ -65,7 +65,7 @@ class _MetadataSectionSliverState extends State<MetadataSectionSliver> with Auto
   Widget build(BuildContext context) {
     super.build(context);
 
-    if (_metadata.isEmpty) return const SliverToBoxAdapter(child: SizedBox.shrink());
+    if (_metadata.isEmpty) return SliverToBoxAdapter(child: SizedBox.shrink());
 
     final directoriesWithoutTitle = _metadata.where((dir) => dir.name.isEmpty).toList();
     final directoriesWithTitle = _metadata.where((dir) => dir.name.isNotEmpty).toList();
@@ -74,7 +74,7 @@ class _MetadataSectionSliverState extends State<MetadataSectionSliver> with Auto
       delegate: SliverChildBuilderDelegate(
         (context, index) {
           if (index == 0) {
-            return const SectionRow(AIcons.info);
+            return SectionRow(AIcons.info);
           }
           if (index < untitledDirectoryCount + 1) {
             final dir = directoriesWithoutTitle[index - 1];
@@ -91,10 +91,10 @@ class _MetadataSectionSliverState extends State<MetadataSectionSliver> with Auto
               expandedNotifier: _expandedDirectoryNotifier,
               title: _DirectoryTitle(dir.name),
               children: [
-                const Divider(thickness: 1.0, height: 1.0),
+                Divider(thickness: 1.0, height: 1.0),
                 Container(
                   alignment: Alignment.topLeft,
-                  padding: const EdgeInsets.all(8),
+                  padding: EdgeInsets.all(8),
                   child: InfoRowGroup(dir.tags),
                 ),
               ],
@@ -150,10 +150,10 @@ class _DirectoryTitle extends StatelessWidget {
         decoration: HighlightDecoration(
           color: stringToColor(name),
         ),
-        margin: const EdgeInsets.symmetric(vertical: 4.0),
+        margin: EdgeInsets.symmetric(vertical: 4.0),
         child: Text(
           name,
-          style: const TextStyle(
+          style: TextStyle(
             shadows: [
               Shadow(
                 color: Colors.black,

lib/widgets/fullscreen/overlay/bottom.dart

@@ -82,15 +82,15 @@ class _FullscreenBottomOverlayState extends State<FullscreenBottomOverlay> {
             return Container(
               color: FullscreenOverlay.backgroundColor,
               padding: viewInsets + viewPadding.copyWith(top: 0),
-              child: FutureBuilder(
+              child: FutureBuilder<OverlayMetadata>(
                 future: _detailLoader,
-                builder: (futureContext, AsyncSnapshot<OverlayMetadata> snapshot) {
+                builder: (futureContext, snapshot) {
                   if (snapshot.connectionState == ConnectionState.done && !snapshot.hasError) {
                     _lastDetails = snapshot.data;
                     _lastEntry = entry;
                   }
                   return _lastEntry == null
-                      ? const SizedBox.shrink()
+                      ? SizedBox.shrink()
                       : Padding(
                           // keep padding inside `FutureBuilder` so that overlay takes no space until data is ready
                           padding: innerPadding,
@@ -134,7 +134,7 @@ class _FullscreenBottomOverlayContent extends AnimatedWidget {
   Widget build(BuildContext context) {
     return DefaultTextStyle(
       style: Theme.of(context).textTheme.bodyText2.copyWith(
-        shadows: const [
+        shadows: [
           Shadow(
             color: Colors.black87,
             offset: Offset(0.5, 1.0),
@@ -163,12 +163,12 @@ class _FullscreenBottomOverlayContent extends AnimatedWidget {
                 if (positionTitle.isNotEmpty) Text(positionTitle, strutStyle: Constants.overflowStrutStyle),
                 if (entry.hasGps)
                   Container(
-                    padding: const EdgeInsets.only(top: _interRowPadding),
+                    padding: EdgeInsets.only(top: _interRowPadding),
                     child: _LocationRow(entry: entry),
                   ),
                 if (twoColumns)
                   Padding(
-                    padding: const EdgeInsets.only(top: _interRowPadding),
+                    padding: EdgeInsets.only(top: _interRowPadding),
                     child: Row(
                       children: [
                         Container(width: subRowWidth, child: _DateRow(entry)),
@@ -178,13 +178,13 @@ class _FullscreenBottomOverlayContent extends AnimatedWidget {
                   )
                 else ...[
                   Container(
-                    padding: const EdgeInsets.only(top: _interRowPadding),
+                    padding: EdgeInsets.only(top: _interRowPadding),
                     width: subRowWidth,
                     child: _DateRow(entry),
                   ),
                   if (hasShootingDetails)
                     Container(
-                      padding: const EdgeInsets.only(top: _interRowPadding),
+                      padding: EdgeInsets.only(top: _interRowPadding),
                       width: subRowWidth,
                       child: _ShootingRow(details),
                     ),
@@ -216,8 +216,8 @@ class _LocationRow extends AnimatedWidget {
     }
     return Row(
       children: [
-        const Icon(AIcons.location, size: _iconSize),
-        const SizedBox(width: _iconPadding),
+        Icon(AIcons.location, size: _iconSize),
+        SizedBox(width: _iconPadding),
         Expanded(child: Text(location, strutStyle: Constants.overflowStrutStyle)),
       ],
     );
@@ -236,8 +236,8 @@ class _DateRow extends StatelessWidget {
     final resolution = '${entry.width ?? '?'} × ${entry.height ?? '?'}';
     return Row(
       children: [
-        const Icon(AIcons.date, size: _iconSize),
-        const SizedBox(width: _iconPadding),
+        Icon(AIcons.date, size: _iconSize),
+        SizedBox(width: _iconPadding),
         Expanded(flex: 3, child: Text(dateText, strutStyle: Constants.overflowStrutStyle)),
         if (!entry.isSvg) Expanded(flex: 2, child: Text(resolution, strutStyle: Constants.overflowStrutStyle)),
       ],
@@ -254,8 +254,8 @@ class _ShootingRow extends StatelessWidget {
   Widget build(BuildContext context) {
     return Row(
       children: [
-        const Icon(AIcons.shooting, size: _iconSize),
-        const SizedBox(width: _iconPadding),
+        Icon(AIcons.shooting, size: _iconSize),
+        SizedBox(width: _iconPadding),
         Expanded(child: Text(details.aperture, strutStyle: Constants.overflowStrutStyle)),
         Expanded(child: Text(details.exposureTime, strutStyle: Constants.overflowStrutStyle)),
         Expanded(child: Text(details.focalLength, strutStyle: Constants.overflowStrutStyle)),

lib/widgets/fullscreen/overlay/top.dart

@@ -40,7 +40,7 @@ class FullscreenTopOverlay extends StatelessWidget {
     return SafeArea(
       minimum: (viewInsets ?? EdgeInsets.zero) + (viewPadding ?? EdgeInsets.zero),
       child: Padding(
-        padding: const EdgeInsets.all(padding),
+        padding: EdgeInsets.all(padding),
         child: Selector<MediaQueryData, Tuple2<double, Orientation>>(
           selector: (c, mq) => Tuple2(mq.size.width, mq.orientation),
           builder: (c, mq, child) {
@@ -126,19 +126,19 @@ class _TopOverlayRow extends StatelessWidget {
       children: [
         OverlayButton(
           scale: scale,
-          child: ModalRoute.of(context)?.canPop ?? true ? const BackButton() : const CloseButton(),
+          child: ModalRoute.of(context)?.canPop ?? true ? BackButton() : CloseButton(),
         ),
-        const Spacer(),
+        Spacer(),
         ...quickActions.map(_buildOverlayButton),
         OverlayButton(
           scale: scale,
           child: PopupMenuButton<EntryAction>(
             itemBuilder: (context) => [
               ...inAppActions.map(_buildPopupMenuItem),
-              const PopupMenuDivider(),
+              PopupMenuDivider(),
               ...externalAppActions.map(_buildPopupMenuItem),
               if (kDebugMode) ...[
-                const PopupMenuDivider(),
+                PopupMenuDivider(),
                 _buildPopupMenuItem(EntryAction.debug),
               ]
             ],
@@ -151,7 +151,7 @@ class _TopOverlayRow extends StatelessWidget {
 
   Widget _buildOverlayButton(EntryAction action) {
     Widget child;
-    final onPressed = () => onActionSelected?.call(action);
+    void onPressed() => onActionSelected?.call(action);
     switch (action) {
       case EntryAction.toggleFavourite:
         child = _FavouriteToggler(
@@ -181,13 +181,13 @@ class _TopOverlayRow extends StatelessWidget {
     }
     return child != null
         ? Padding(
-            padding: const EdgeInsetsDirectional.only(end: padding),
+            padding: EdgeInsetsDirectional.only(end: padding),
             child: OverlayButton(
               scale: scale,
               child: child,
             ),
           )
-        : const SizedBox.shrink();
+        : SizedBox.shrink();
   }
 
   PopupMenuEntry<EntryAction> _buildPopupMenuItem(EntryAction action) {
@@ -269,11 +269,11 @@ class _FavouriteTogglerState extends State<_FavouriteToggler> {
       builder: (context, isFavourite, child) {
         if (widget.isMenuItem) {
           return isFavourite
-              ? const MenuRow(
+              ? MenuRow(
                   text: 'Remove from favourites',
                   icon: AIcons.favouriteActive,
                 )
-              : const MenuRow(
+              : MenuRow(
                   text: 'Add to favourites',
                   icon: AIcons.favourite,
                 );
@@ -288,7 +288,7 @@ class _FavouriteTogglerState extends State<_FavouriteToggler> {
             ),
             Sweeper(
               key: ValueKey(widget.entry),
-              builder: (context) => const Icon(AIcons.favourite, color: Colors.redAccent),
+              builder: (context) => Icon(AIcons.favourite, color: Colors.redAccent),
               toggledNotifier: isFavouriteNotifier,
             ),
           ],

lib/widgets/fullscreen/overlay/video.dart

@@ -98,14 +98,14 @@ class VideoControlOverlayState extends State<VideoControlOverlay> with SingleTic
 
   @override
   Widget build(BuildContext context) {
-    final mq = context.select((MediaQueryData mq) => Tuple3(mq.size.width, mq.viewInsets, mq.viewPadding));
+    final mq = context.select<MediaQueryData, Tuple3<double, EdgeInsets, EdgeInsets>>((mq) => Tuple3(mq.size.width, mq.viewInsets, mq.viewPadding));
     final mqWidth = mq.item1;
     final mqViewInsets = mq.item2;
     final mqViewPadding = mq.item3;
 
     final viewInsets = widget.viewInsets ?? mqViewInsets;
     final viewPadding = widget.viewPadding ?? mqViewPadding;
-    final safePadding = (viewInsets + viewPadding).copyWith(bottom: 8) + const EdgeInsets.symmetric(horizontal: 8.0);
+    final safePadding = (viewInsets + viewPadding).copyWith(bottom: 8) + EdgeInsets.symmetric(horizontal: 8.0);
 
     return Padding(
       padding: safePadding,
@@ -127,7 +127,7 @@ class VideoControlOverlayState extends State<VideoControlOverlay> with SingleTic
                           OverlayButton(
                             scale: scale,
                             child: IconButton(
-                              icon: const Icon(AIcons.openInNew),
+                              icon: Icon(AIcons.openInNew),
                               onPressed: () => AndroidAppService.open(entry.uri, entry.mimeTypeAnySubtype),
                               tooltip: 'Open',
                             ),
@@ -137,7 +137,7 @@ class VideoControlOverlayState extends State<VideoControlOverlay> with SingleTic
                           Expanded(
                             child: _buildProgressBar(),
                           ),
-                          const SizedBox(width: 8),
+                          SizedBox(width: 8),
                           OverlayButton(
                             scale: scale,
                             child: IconButton(
@@ -164,25 +164,25 @@ class VideoControlOverlayState extends State<VideoControlOverlay> with SingleTic
       child: BlurredRRect(
         borderRadius: progressBarBorderRadius,
         child: GestureDetector(
-          onTapDown: (TapDownDetails details) {
+          onTapDown: (details) {
             _seekFromTap(details.globalPosition);
           },
-          onHorizontalDragStart: (DragStartDetails details) {
+          onHorizontalDragStart: (details) {
             _playingOnDragStart = isPlaying;
             if (_playingOnDragStart) controller.pause();
           },
-          onHorizontalDragUpdate: (DragUpdateDetails details) {
+          onHorizontalDragUpdate: (details) {
             _seekFromTap(details.globalPosition);
           },
-          onHorizontalDragEnd: (DragEndDetails details) {
+          onHorizontalDragEnd: (details) {
             if (_playingOnDragStart) controller.play();
           },
           child: Container(
-            padding: const EdgeInsets.symmetric(vertical: 4, horizontal: 16) + const EdgeInsets.only(bottom: 16),
+            padding: EdgeInsets.symmetric(vertical: 4, horizontal: 16) + EdgeInsets.only(bottom: 16),
             decoration: BoxDecoration(
               color: FullscreenOverlay.backgroundColor,
               border: FullscreenOverlay.buildBorder(context),
-              borderRadius: const BorderRadius.all(
+              borderRadius: BorderRadius.all(
                 Radius.circular(progressBarBorderRadius),
               ),
             ),
@@ -198,7 +198,7 @@ class VideoControlOverlayState extends State<VideoControlOverlay> with SingleTic
                           final position = videoInfo.currentPosition?.floor() ?? 0;
                           return Text(formatDuration(Duration(seconds: position)));
                         }),
-                    const Spacer(),
+                    Spacer(),
                     Text(entry.durationText),
                   ],
                 ),

lib/widgets/fullscreen/video_view.dart

@@ -60,7 +60,7 @@ class AvesVideoState extends State<AvesVideo> {
 
   @override
   Widget build(BuildContext context) {
-    if (controller == null) return const SizedBox();
+    if (controller == null) return SizedBox();
     return StreamBuilder<IjkStatus>(
         stream: widget.controller.ijkStatusStream,
         builder: (context, snapshot) {
@@ -68,8 +68,8 @@ class AvesVideoState extends State<AvesVideo> {
           return isPlayable(status)
               ? IjkPlayer(
                   mediaController: controller,
-                  controllerWidgetBuilder: (controller) => const SizedBox.shrink(),
-                  statusWidgetBuilder: (context, controller, status) => const SizedBox.shrink(),
+                  controllerWidgetBuilder: (controller) => SizedBox.shrink(),
+                  statusWidgetBuilder: (context, controller, status) => SizedBox.shrink(),
                   textureBuilder: (context, controller, info) {
                     var id = controller.textureId;
                     var child = id != null

lib/widgets/home_page.dart

@@ -68,7 +68,7 @@ class _HomePageState extends State<HomePage> {
           // TODO TLAD apply pick mimetype(s)
           // some apps define multiple types, separated by a space (maybe other signs too, like `,` `;`?)
           String pickMimeTypes = intentData['mimeType'];
-          debugPrint('pick mimeType=' + pickMimeTypes);
+          debugPrint('pick mimeType=$pickMimeTypes');
           break;
       }
     }
@@ -92,11 +92,11 @@ class _HomePageState extends State<HomePage> {
 
   @override
   Widget build(BuildContext context) {
-    return FutureBuilder(
+    return FutureBuilder<void>(
         future: _appSetup,
-        builder: (context, AsyncSnapshot<void> snapshot) {
-          if (snapshot.hasError) return const Icon(AIcons.error);
-          if (snapshot.connectionState != ConnectionState.done) return const Scaffold();
+        builder: (context, snapshot) {
+          if (snapshot.hasError) return Icon(AIcons.error);
+          if (snapshot.connectionState != ConnectionState.done) return Scaffold();
           if (AvesApp.mode == AppMode.view) {
             return SingleFullscreenPage(entry: _viewerEntry);
           }
@@ -107,7 +107,7 @@ class _HomePageState extends State<HomePage> {
               sortFactor: settings.collectionSortFactor,
             ));
           }
-          return const SizedBox.shrink();
+          return SizedBox.shrink();
         });
   }
 }

lib/widgets/stats/filter_table.dart

@@ -36,7 +36,7 @@ class FilterTable extends StatelessWidget {
     final lineHeight = 16 * textScaleFactor;
 
     return Padding(
-      padding: const EdgeInsetsDirectional.only(start: AvesFilterChip.outlineWidth / 2 + 6, end: 8),
+      padding: EdgeInsetsDirectional.only(start: AvesFilterChip.outlineWidth / 2 + 6, end: 8),
       child: LayoutBuilder(
         builder: (context, constraints) {
           final showPercentIndicator = constraints.maxWidth - (chipWidth + countWidth) > percentIndicatorMinWidth;
@@ -49,7 +49,7 @@ class FilterTable extends StatelessWidget {
               return TableRow(
                 children: [
                   Container(
-                    padding: const EdgeInsets.only(bottom: 8),
+                    padding: EdgeInsets.only(bottom: 8),
                     alignment: AlignmentDirectional.centerStart,
                     child: AvesFilterChip(
                       filter: filter,
@@ -67,14 +67,14 @@ class FilterTable extends StatelessWidget {
                       center: Text(NumberFormat.percentPattern().format(percent)),
                     ),
                   Text(
-                    '${count}',
-                    style: const TextStyle(color: Colors.white70),
+                    '$count',
+                    style: TextStyle(color: Colors.white70),
                     textAlign: TextAlign.end,
                   ),
                 ],
               );
             }).toList(),
-            columnWidths: const {
+            columnWidths: {
               0: MaxColumnWidth(IntrinsicColumnWidth(), FixedColumnWidth(chipWidth)),
               2: MaxColumnWidth(IntrinsicColumnWidth(), FixedColumnWidth(countWidth)),
             },

lib/widgets/stats/stats.dart

@@ -1,10 +1,10 @@
 import 'dart:math';
 
-import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/model/filters/filters.dart';
 import 'package:aves/model/filters/location.dart';
 import 'package:aves/model/filters/tag.dart';
 import 'package:aves/model/image_entry.dart';
+import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/utils/color_utils.dart';
 import 'package:aves/utils/constants.dart';
 import 'package:aves/widgets/album/empty.dart';
@@ -49,12 +49,12 @@ class StatsPage extends StatelessWidget {
   Widget build(BuildContext context) {
     Widget child;
     if (collection.isEmpty) {
-      child = const EmptyContent(
+      child = EmptyContent(
         icon: AIcons.image,
         text: 'No images',
       );
     } else {
-      final byMimeTypes = groupBy(entries, (entry) => entry.mimeType).map<String, int>((k, v) => MapEntry(k, v.length));
+      final byMimeTypes = groupBy<ImageEntry, String>(entries, (entry) => entry.mimeType).map<String, int>((k, v) => MapEntry(k, v.length));
       final imagesByMimeTypes = Map.fromEntries(byMimeTypes.entries.where((kv) => kv.key.startsWith('image/')));
       final videoByMimeTypes = Map.fromEntries(byMimeTypes.entries.where((kv) => kv.key.startsWith('video/')));
       final mimeDonuts = Wrap(
@@ -71,7 +71,7 @@ class StatsPage extends StatelessWidget {
       final textScaleFactor = MediaQuery.textScaleFactorOf(context);
       final lineHeight = 16 * textScaleFactor;
       final locationIndicator = Padding(
-        padding: const EdgeInsets.all(16),
+        padding: EdgeInsets.all(16),
         child: Column(
           children: [
             LinearPercentIndicator(
@@ -80,12 +80,12 @@ class StatsPage extends StatelessWidget {
               backgroundColor: Colors.white24,
               progressColor: Theme.of(context).accentColor,
               animation: true,
-              leading: const Icon(AIcons.location),
+              leading: Icon(AIcons.location),
               // right padding to match leading, so that inside label is aligned with outside label below
-              padding: EdgeInsets.symmetric(horizontal: lineHeight) + const EdgeInsets.only(right: 24),
+              padding: EdgeInsets.symmetric(horizontal: lineHeight) + EdgeInsets.only(right: 24),
               center: Text(NumberFormat.percentPattern().format(withGpsPercent)),
             ),
-            const SizedBox(height: 8),
+            SizedBox(height: 8),
             Text('${withGps.length} ${Intl.plural(withGps.length, one: 'item', other: 'items')} with location'),
           ],
         ),
@@ -103,7 +103,7 @@ class StatsPage extends StatelessWidget {
     return MediaQueryDataProvider(
       child: Scaffold(
         appBar: AppBar(
-          title: const Text('Stats'),
+          title: Text('Stats'),
         ),
         body: SafeArea(
           child: child,
@@ -118,9 +118,9 @@ class StatsPage extends StatelessWidget {
   }
 
   Widget _buildMimeDonut(BuildContext context, String Function(num) label, Map<String, num> byMimeTypes) {
-    if (byMimeTypes.isEmpty) return const SizedBox.shrink();
+    if (byMimeTypes.isEmpty) return SizedBox.shrink();
 
-    final sum = byMimeTypes.values.fold(0, (prev, v) => prev + v);
+    final sum = byMimeTypes.values.fold<int>(0, (prev, v) => prev + v);
 
     final seriesData = byMimeTypes.entries.map((kv) => StringNumDatum(_cleanMime(kv.key), kv.value)).toList();
     seriesData.sort((kv1, kv2) {
@@ -158,7 +158,7 @@ class StatsPage extends StatelessWidget {
             ),
             Center(
               child: Text(
-                '${sum}\n${label(sum)}',
+                '$sum\n${label(sum)}',
                 textAlign: TextAlign.center,
               ),
             ),
@@ -177,12 +177,12 @@ class StatsPage extends StatelessWidget {
                         WidgetSpan(
                           alignment: PlaceholderAlignment.middle,
                           child: Padding(
-                            padding: const EdgeInsetsDirectional.only(end: 8),
+                            padding: EdgeInsetsDirectional.only(end: 8),
                             child: Icon(AIcons.disc, color: stringToColor(kv.key)),
                           ),
                         ),
                         TextSpan(text: '${kv.key}   '),
-                        TextSpan(text: '${kv.value}', style: const TextStyle(color: Colors.white70)),
+                        TextSpan(text: '${kv.value}', style: TextStyle(color: Colors.white70)),
                       ],
                     ),
                     overflow: TextOverflow.fade,
@@ -217,7 +217,7 @@ class StatsPage extends StatelessWidget {
 
     return [
       Padding(
-        padding: const EdgeInsets.all(16),
+        padding: EdgeInsets.all(16),
         child: Text(
           title,
           style: Constants.titleTextStyle,

lib/widgets/welcome_page.dart

@@ -32,11 +32,11 @@ class _WelcomePageState extends State<WelcomePage> {
       body: SafeArea(
         child: Container(
           alignment: Alignment.center,
-          padding: const EdgeInsets.all(16.0),
-          child: FutureBuilder(
+          padding: EdgeInsets.all(16.0),
+          child: FutureBuilder<String>(
               future: _termsLoader,
-              builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
-                if (snapshot.hasError || snapshot.connectionState != ConnectionState.done) return const SizedBox.shrink();
+              builder: (context, snapshot) {
+                if (snapshot.hasError || snapshot.connectionState != ConnectionState.done) return SizedBox.shrink();
                 final terms = snapshot.data;
                 return Column(
                   mainAxisSize: MainAxisSize.min,
@@ -73,21 +73,21 @@ class _WelcomePageState extends State<WelcomePage> {
     return [
       ...(MediaQuery.of(context).orientation == Orientation.portrait
           ? [
-              const AvesLogo(size: 64),
-              const SizedBox(height: 16),
+              AvesLogo(size: 64),
+              SizedBox(height: 16),
               message,
             ]
           : [
               Row(
                 mainAxisSize: MainAxisSize.min,
                 children: [
-                  const AvesLogo(size: 48),
-                  const SizedBox(width: 16),
+                  AvesLogo(size: 48),
+                  SizedBox(width: 16),
                   message,
                 ],
               )
             ]),
-      const SizedBox(height: 16),
+      SizedBox(height: 16),
     ];
   }
 
@@ -98,14 +98,14 @@ class _WelcomePageState extends State<WelcomePage> {
       text: 'I agree to the terms and conditions',
     );
     final button = RaisedButton(
-      child: const Text('Continue'),
+      child: Text('Continue'),
       onPressed: _hasAcceptedTerms
           ? () {
               settings.hasAcceptedTerms = true;
               Navigator.pushAndRemoveUntil(
                 context,
                 MaterialPageRoute(
-                  builder: (context) => const HomePage(),
+                  builder: (context) => HomePage(),
                 ),
                 (route) => false,
               );
@@ -118,11 +118,11 @@ class _WelcomePageState extends State<WelcomePage> {
             button,
           ]
         : [
-            const SizedBox(height: 16),
+            SizedBox(height: 16),
             Row(
               children: [
                 checkbox,
-                const Spacer(),
+                Spacer(),
                 button,
               ],
             ),
@@ -135,7 +135,7 @@ class _WelcomePageState extends State<WelcomePage> {
         borderRadius: BorderRadius.circular(16),
         color: Colors.white10,
       ),
-      constraints: const BoxConstraints(maxWidth: 460),
+      constraints: BoxConstraints(maxWidth: 460),
       child: ClipRRect(
         borderRadius: BorderRadius.circular(16),
         child: Markdown(

pubspec.lock

@@ -28,7 +28,7 @@ packages:
       name: barcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.13.0"
+    version: "1.14.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -103,6 +103,13 @@ packages:
       url: "git://github.com/deckerst/expansion_tile_card.git"
     source: git
     version: "1.0.3"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.2.1"
   firebase_crashlytics:
     dependency: "direct main"
     description:
@@ -295,6 +302,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.1.4"
+  path_provider_linux:
+    dependency: transitive
+    description:
+      name: path_provider_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+2"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.2"
   pdf:
     dependency: "direct main"
     description:
@@ -346,6 +367,13 @@ packages:
       url: "git://github.com/deckerst/photo_view.git"
     source: git
     version: "0.9.2"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.1"
   platform_detect:
     dependency: transitive
     description:
@@ -367,13 +395,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.5.0"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.13"
   provider:
     dependency: "direct main"
     description:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "4.1.3"
+    version: "4.3.1"
   pub_semver:
     dependency: transitive
     description:
@@ -408,7 +443,14 @@ packages:
       name: shared_preferences
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.7+3"
+    version: "0.5.8"
+  shared_preferences_linux:
+    dependency: transitive
+    description:
+      name: shared_preferences_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.2+1"
   shared_preferences_macos:
     dependency: transitive
     description:
@@ -497,7 +539,7 @@ packages:
       name: synchronized
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0+1"
+    version: "2.2.0+2"
   term_glyph:
     dependency: transitive
     description:
@@ -532,7 +574,14 @@ packages:
       name: url_launcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "5.4.11"
+    version: "5.5.0"
+  url_launcher_linux:
+    dependency: transitive
+    description:
+      name: url_launcher_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+1"
   url_launcher_macos:
     dependency: transitive
     description:
@@ -575,6 +624,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.8"
+  xdg_directories:
+    dependency: transitive
+    description:
+      name: xdg_directories
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.0"
   xml:
     dependency: transitive
     description:

pubspec.yaml

@@ -11,7 +11,7 @@ description: A new Flutter application.
 # In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
-version: 1.0.10+11
+version: 1.1.0+12
 
 # video_player (as of v0.10.8+2, backed by ExoPlayer):
 # - does not support content URIs (by default, but trivial by fork)

test/widget_test.dart

@@ -0,0 +1,8 @@
+import 'package:aves/main.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('TODO TLAD', (tester) async {
+    await tester.pumpWidget(AvesApp());
+  });
+}