improved error reporting when requesting directory permission

android/app/src/main/kotlin/deckers/thibault/aves/AnalysisService.kt

@@ -17,7 +17,6 @@ import deckers.thibault.aves.channel.calls.MediaStoreHandler
 import deckers.thibault.aves.channel.calls.MetadataFetchHandler
 import deckers.thibault.aves.channel.streams.ImageByteStreamHandler
 import deckers.thibault.aves.channel.streams.MediaStoreStreamHandler
-import deckers.thibault.aves.utils.ContextUtils.runOnUiThread
 import deckers.thibault.aves.utils.FlutterUtils
 import deckers.thibault.aves.utils.LogUtils
 import io.flutter.embedding.engine.FlutterEngine
@@ -155,12 +154,11 @@ class AnalysisService : MethodChannel.MethodCallHandler, Service() {
 
     private inner class ServiceHandler(looper: Looper) : Handler(looper) {
         override fun handleMessage(msg: Message) {
-            val context = this@AnalysisService
             val data = msg.data
             when (data.getString(KEY_COMMAND)) {
                 COMMAND_START -> {
                     runBlocking {
-                        context.runOnUiThread {
+                        FlutterUtils.runOnUiThread {
                             val contentIds = data.get(KEY_CONTENT_IDS)?.takeIf { it is IntArray }?.let { (it as IntArray).toList() }
                             backgroundChannel?.invokeMethod(
                                 "start", hashMapOf(
@@ -174,7 +172,7 @@ class AnalysisService : MethodChannel.MethodCallHandler, Service() {
                 COMMAND_STOP -> {
                     // unconditionally stop the service
                     runBlocking {
-                        context.runOnUiThread {
+                        FlutterUtils.runOnUiThread {
                             backgroundChannel?.invokeMethod("stop", null)
                         }
                     }

android/app/src/main/kotlin/deckers/thibault/aves/MainActivity.kt

@@ -311,7 +311,10 @@ class MainActivity : FlutterActivity() {
 
         var errorStreamHandler: ErrorStreamHandler? = null
 
-        fun notifyError(error: String) = errorStreamHandler?.notifyError(error)
+        suspend fun notifyError(error: String) {
+            Log.e(LOG_TAG, "notifyError error=$error")
+            errorStreamHandler?.notifyError(error)
+        }
     }
 }
 

android/app/src/main/kotlin/deckers/thibault/aves/SearchSuggestionsProvider.kt

@@ -12,7 +12,6 @@ import android.text.format.DateFormat
 import android.util.Log
 import deckers.thibault.aves.model.FieldMap
 import deckers.thibault.aves.utils.ContextUtils.resourceUri
-import deckers.thibault.aves.utils.ContextUtils.runOnUiThread
 import deckers.thibault.aves.utils.FlutterUtils
 import deckers.thibault.aves.utils.LogUtils
 import io.flutter.embedding.engine.FlutterEngine
@@ -80,7 +79,7 @@ class SearchSuggestionsProvider : MethodChannel.MethodCallHandler, ContentProvid
 
         return suspendCoroutine { cont ->
             GlobalScope.launch {
-                context.runOnUiThread {
+                FlutterUtils.runOnUiThread {
                     backgroundChannel.invokeMethod("getSuggestions", hashMapOf(
                         "query" to query,
                         "locale" to Locale.getDefault().toString(),

android/app/src/main/kotlin/deckers/thibault/aves/channel/streams/ErrorStreamHandler.kt

@@ -1,5 +1,6 @@
 package deckers.thibault.aves.channel.streams
 
+import deckers.thibault.aves.utils.FlutterUtils
 import io.flutter.plugin.common.EventChannel
 import io.flutter.plugin.common.EventChannel.EventSink
 
@@ -15,9 +16,11 @@ class ErrorStreamHandler : EventChannel.StreamHandler {
 
     override fun onCancel(arguments: Any?) {}
 
-    fun notifyError(error: String) {
+    suspend fun notifyError(error: String) {
+        FlutterUtils.runOnUiThread {
             eventSink?.success(error)
         }
+    }
 
     companion object {
         const val CHANNEL = "deckers.thibault/aves/error"

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

@@ -49,7 +49,7 @@ class StorageAccessStreamHandler(private val activity: Activity, arguments: Any?
         }
     }
 
-    private fun requestDirectoryAccess() {
+    private suspend fun requestDirectoryAccess() {
         val path = args["path"] as String?
         if (path == null) {
             error("requestDirectoryAccess-args", "failed because of missing arguments", null)

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

@@ -323,6 +323,7 @@ class MediaStoreImageProvider : ImageProvider() {
                 // with a path, and retrieve its content URI, but:
                 // - the Media Store isolates content by storage volume (e.g. `MediaStore.Images.Media.getContentUri(volumeName)`)
                 // - the volume name should be lower case, not exactly as the `StorageVolume` UUID
+                //   cf new method in API 30 `StorageVolume.getMediaStoreVolumeName()`
                 // - inserting on a removable volume works on API 29, but not on API 25 nor 26 (on which API/devices does it work?)
                 // - 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

android/app/src/main/kotlin/deckers/thibault/aves/utils/ContextUtils.kt

@@ -5,10 +5,6 @@ import android.app.Service
 import android.content.ContentResolver
 import android.content.Context
 import android.net.Uri
-import android.os.Handler
-import android.os.Looper
-import kotlin.coroutines.resume
-import kotlin.coroutines.suspendCoroutine
 
 object ContextUtils {
     fun Context.resourceUri(resourceId: Int): Uri = with(resources) {
@@ -20,19 +16,6 @@ object ContextUtils {
             .build()
     }
 
-    suspend fun Context.runOnUiThread(r: Runnable) {
-        if (Looper.myLooper() != mainLooper) {
-            suspendCoroutine<Boolean> { cont ->
-                Handler(mainLooper).post {
-                    r.run()
-                    cont.resume(true)
-                }
-            }
-        } else {
-            r.run()
-        }
-    }
-
     fun Context.isMyServiceRunning(serviceClass: Class<out Service>): Boolean {
         val am = this.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager?
         am ?: return false

android/app/src/main/kotlin/deckers/thibault/aves/utils/FlutterUtils.kt

@@ -1,13 +1,16 @@
 package deckers.thibault.aves.utils
 
 import android.content.Context
+import android.os.Handler
+import android.os.Looper
 import android.util.Log
-import deckers.thibault.aves.utils.ContextUtils.runOnUiThread
 import io.flutter.FlutterInjector
 import io.flutter.embedding.engine.FlutterEngine
 import io.flutter.embedding.engine.dart.DartExecutor
 import io.flutter.embedding.engine.loader.FlutterLoader
 import io.flutter.view.FlutterCallbackInformation
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
 
 object FlutterUtils {
     private val LOG_TAG = LogUtils.createTag<FlutterUtils>()
@@ -20,7 +23,7 @@ object FlutterUtils {
         }
 
         lateinit var flutterLoader: FlutterLoader
-        context.runOnUiThread {
+        FlutterUtils.runOnUiThread {
             // initialization must happen on the main thread
             flutterLoader = FlutterInjector.instance().flutterLoader().apply {
                 startInitialization(context)
@@ -39,11 +42,25 @@ object FlutterUtils {
             flutterLoader.findAppBundlePath(),
             callbackInfo
         )
-        context.runOnUiThread {
+        runOnUiThread {
             val engine = FlutterEngine(context).apply {
                 dartExecutor.executeDartCallback(args)
             }
             engineSetter(engine)
         }
     }
+
+    suspend fun runOnUiThread(r: Runnable) {
+        val mainLooper = Looper.getMainLooper()
+        if (Looper.myLooper() != mainLooper) {
+            suspendCoroutine<Boolean> { cont ->
+                Handler(mainLooper).post {
+                    r.run()
+                    cont.resume(true)
+                }
+            }
+        } else {
+            r.run()
+        }
+    }
 }

android/app/src/main/kotlin/deckers/thibault/aves/utils/PermissionManager.kt

@@ -31,13 +31,18 @@ object PermissionManager {
     )
 
     @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
-    fun requestDirectoryAccess(activity: Activity, path: String, onGranted: (uri: Uri) -> Unit, onDenied: () -> Unit) {
+    suspend fun requestDirectoryAccess(activity: Activity, path: String, onGranted: (uri: Uri) -> Unit, onDenied: () -> Unit) {
         Log.i(LOG_TAG, "request user to select and grant access permission to path=$path")
 
         var intent: Intent? = null
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             val sm = activity.getSystemService(Context.STORAGE_SERVICE) as? StorageManager
-            intent = sm?.getStorageVolume(File(path))?.createOpenDocumentTreeIntent()
+            val storageVolume = sm?.getStorageVolume(File(path))
+            if (storageVolume != null) {
+                intent = storageVolume.createOpenDocumentTreeIntent()
+            } else {
+                MainActivity.notifyError("failed to get storage volume for path=$path on volumes=${sm?.storageVolumes?.joinToString(", ")}")
+            }
         }
 
         // fallback to basic open document tree intent
@@ -49,7 +54,7 @@ object PermissionManager {
             MainActivity.pendingStorageAccessResultHandlers[MainActivity.DOCUMENT_TREE_ACCESS_REQUEST] = PendingStorageAccessResultHandler(path, onGranted, onDenied)
             activity.startActivityForResult(intent, MainActivity.DOCUMENT_TREE_ACCESS_REQUEST)
         } else {
-            Log.e(LOG_TAG, "failed to resolve activity for intent=$intent")
+            MainActivity.notifyError("failed to resolve activity for intent=$intent")
             onDenied()
         }
     }