info: restored metadata section code, and fixed animation limiter scope

lib/widgets/fullscreen/info/info_page.dart

@@ -1,9 +1,6 @@
-import 'dart:collection';
-
 import 'package:aves/model/filters/filters.dart';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/source/collection_lens.dart';
-import 'package:aves/services/metadata_service.dart';
 import 'package:aves/utils/durations.dart';
 import 'package:aves/widgets/common/data_providers/media_query_data_provider.dart';
 import 'package:aves/widgets/common/icons.dart';
@@ -11,9 +8,7 @@ import 'package:aves/widgets/fullscreen/info/basic_section.dart';
 import 'package:aves/widgets/fullscreen/info/location_section.dart';
 import 'package:aves/widgets/fullscreen/info/metadata_section.dart';
 import 'package:aves/widgets/fullscreen/info/notifications.dart';
-import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
 import 'package:provider/provider.dart';
 import 'package:tuple/tuple.dart';
 
@@ -146,48 +141,12 @@ class _InfoPageContent extends StatefulWidget {
 }
 
 class _InfoPageContentState extends State<_InfoPageContent> {
-  List<MetadataDirectory> _metadata = [];
-  String _loadedMetadataUri;
-
   static const horizontalPadding = EdgeInsets.symmetric(horizontal: 8);
 
   CollectionLens get collection => widget.collection;
 
   ImageEntry get entry => widget.entry;
 
-  bool get isVisible => widget.visibleNotifier.value;
-
-  @override
-  void initState() {
-    super.initState();
-    _registerWidget(widget);
-    _getMetadata();
-  }
-
-  @override
-  void didUpdateWidget(_InfoPageContent oldWidget) {
-    super.didUpdateWidget(oldWidget);
-    _unregisterWidget(oldWidget);
-    _registerWidget(widget);
-    _getMetadata();
-  }
-
-  @override
-  void dispose() {
-    _unregisterWidget(widget);
-    super.dispose();
-  }
-
-  void _registerWidget(_InfoPageContent widget) {
-    widget.visibleNotifier.addListener(_getMetadata);
-    widget.entry.metadataChangeNotifier.addListener(_onMetadataChanged);
-  }
-
-  void _unregisterWidget(_InfoPageContent widget) {
-    widget.visibleNotifier.removeListener(_getMetadata);
-    widget.entry.metadataChangeNotifier.removeListener(_onMetadataChanged);
-  }
-
   @override
   Widget build(BuildContext context) {
     final locationAtTop = widget.split && entry.hasGps;
@@ -219,14 +178,10 @@ class _InfoPageContentState extends State<_InfoPageContent> {
           );
     final metadataSliver = MetadataSectionSliver(
       entry: entry,
-      metadata: _metadata,
+      visibleNotifier: widget.visibleNotifier,
     );
 
-    return AnimationLimiter(
+    return CustomScrollView(
-      // we update the limiter key after fetching the metadata of a new entry,
-      // in order to restart the staggered animation of the metadata section
-      key: Key(_loadedMetadataUri),
-      child: CustomScrollView(
       controller: widget.scrollController,
       slivers: [
         widget.appBar,
@@ -239,7 +194,6 @@ class _InfoPageContentState extends State<_InfoPageContent> {
           sliver: metadataSliver,
         ),
       ],
-      ),
     );
   }
 
@@ -247,38 +201,4 @@ class _InfoPageContentState extends State<_InfoPageContent> {
     if (collection == null) return;
     FilterNotification(filter).dispatch(context);
   }
-
-  void _onMetadataChanged() {
-    _metadata = [];
-    _loadedMetadataUri = null;
-    _getMetadata();
-  }
-
-  // fetch and hold metadata in the page widget and not in the section sliver,
-  // so that we can refresh and limit the staggered animation of the metadata section
-  Future<void> _getMetadata() async {
-    if (entry == null) return;
-    if (_loadedMetadataUri == entry.uri) return;
-    if (isVisible) {
-      final rawMetadata = await MetadataService.getAllMetadata(entry) ?? {};
-      _metadata = rawMetadata.entries.map((dirKV) {
-        final directoryName = dirKV.key as String ?? '';
-        final rawTags = dirKV.value as Map ?? {};
-        final tags = SplayTreeMap.of(Map.fromEntries(rawTags.entries.map((tagKV) {
-          final value = tagKV.value as String ?? '';
-          if (value.isEmpty) return null;
-          final tagName = tagKV.key as String ?? '';
-          return MapEntry(tagName, value);
-        }).where((kv) => kv != null)));
-        return MetadataDirectory(directoryName, tags);
-      }).toList()
-        ..sort((a, b) => compareAsciiUpperCase(a.name, b.name));
-      _loadedMetadataUri = entry.uri;
-    } else {
-      _metadata = [];
-      _loadedMetadataUri = null;
-    }
-    // _expandedDirectoryNotifier.value = null;
-    if (mounted) setState(() {});
-  }
 }

lib/widgets/fullscreen/info/metadata_section.dart

@@ -1,82 +1,127 @@
 import 'dart:collection';
 
 import 'package:aves/model/image_entry.dart';
+import 'package:aves/services/metadata_service.dart';
 import 'package:aves/utils/constants.dart';
 import 'package:aves/utils/durations.dart';
 import 'package:aves/widgets/common/aves_expansion_tile.dart';
 import 'package:aves/widgets/common/icons.dart';
 import 'package:aves/widgets/fullscreen/info/common.dart';
 import 'package:aves/widgets/fullscreen/info/metadata_thumbnail.dart';
+import 'package:collection/collection.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
 
 class MetadataSectionSliver extends StatefulWidget {
   final ImageEntry entry;
-  final List<MetadataDirectory> metadata;
+  final ValueNotifier<bool> visibleNotifier;
 
   const MetadataSectionSliver({
     @required this.entry,
-    @required this.metadata,
+    @required this.visibleNotifier,
   });
 
   @override
-  State<StatefulWidget> createState() => metadataSectionSliverState();
+  State<StatefulWidget> createState() => _MetadataSectionSliverState();
 }
 
-class metadataSectionSliverState extends State<MetadataSectionSliver> with AutomaticKeepAliveClientMixin {
+class _MetadataSectionSliverState extends State<MetadataSectionSliver> with AutomaticKeepAliveClientMixin {
+  List<_MetadataDirectory> _metadata = [];
+  final ValueNotifier<String> _loadedMetadataUri = ValueNotifier(null);
   final ValueNotifier<String> _expandedDirectoryNotifier = ValueNotifier(null);
 
   ImageEntry get entry => widget.entry;
 
-  List<MetadataDirectory> get metadata => widget.metadata;
+  bool get isVisible => widget.visibleNotifier.value;
 
   // special directory names
   static const exifThumbnailDirectory = 'Exif Thumbnail'; // from metadata-extractor
   static const xmpDirectory = 'XMP'; // from metadata-extractor
   static const mediaDirectory = 'Media'; // additional media (video/audio/images) directory
 
+  @override
+  void initState() {
+    super.initState();
+    _registerWidget(widget);
+    _getMetadata();
+  }
+
+  @override
+  void didUpdateWidget(MetadataSectionSliver oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    _unregisterWidget(oldWidget);
+    _registerWidget(widget);
+    _getMetadata();
+  }
+
+  @override
+  void dispose() {
+    _unregisterWidget(widget);
+    super.dispose();
+  }
+
+  void _registerWidget(MetadataSectionSliver widget) {
+    widget.visibleNotifier.addListener(_getMetadata);
+    widget.entry.metadataChangeNotifier.addListener(_onMetadataChanged);
+  }
+
+  void _unregisterWidget(MetadataSectionSliver widget) {
+    widget.visibleNotifier.removeListener(_getMetadata);
+    widget.entry.metadataChangeNotifier.removeListener(_onMetadataChanged);
+  }
+
   @override
   Widget build(BuildContext context) {
     super.build(context);
-
+    // use a `Column` inside a `SliverToBoxAdapter`, instead of a `SliverList`,
-    if (metadata.isEmpty) return SliverToBoxAdapter(child: SizedBox.shrink());
+    // so that we can have the metadata-dependent `AnimationLimiter` inside the metadata section
-
+    // warning: placing the `AnimationLimiter` as a parent to the `ScrollView`
-    final directoriesWithoutTitle = metadata.where((dir) => dir.name.isEmpty).toList();
+    // triggers dispose & reinitialization of other sections, including heavy widgets like maps
-    final directoriesWithTitle = metadata.where((dir) => dir.name.isNotEmpty).toList();
+    return SliverToBoxAdapter(
-    final untitledDirectoryCount = directoriesWithoutTitle.length;
+      child: AnimatedBuilder(
-    return SliverList(
+        animation: _loadedMetadataUri,
-      delegate: SliverChildBuilderDelegate(
+        builder: (context, child) {
-        (context, index) {
+          Widget content;
-          Widget child;
+          if (_metadata.isEmpty) {
-          if (index == 0) {
+            content = SizedBox.shrink();
-            child = SectionRow(AIcons.info);
-          } else if (index < untitledDirectoryCount + 1) {
-            child = _buildDirTileWithoutTitle(directoriesWithoutTitle[index - 1]);
           } else {
-            child = _buildDirTileWithTitle(directoriesWithTitle[index - 1 - untitledDirectoryCount]);
+            final directoriesWithoutTitle = _metadata.where((dir) => dir.name.isEmpty).toList();
-          }
+            final directoriesWithTitle = _metadata.where((dir) => dir.name.isNotEmpty).toList();
-          return AnimationConfiguration.staggeredList(
+            content = Column(
-            position: index,
+              children: AnimationConfiguration.toStaggeredList(
                 duration: Durations.staggeredAnimation,
                 delay: Durations.staggeredAnimationDelay,
-            child: SlideAnimation(
+                childAnimationBuilder: (child) => SlideAnimation(
                   verticalOffset: 50.0,
                   child: FadeInAnimation(
                     child: child,
                   ),
                 ),
+                children: [
+                  SectionRow(AIcons.info),
+                  ...directoriesWithoutTitle.map(_buildDirTileWithoutTitle),
+                  ...directoriesWithTitle.map(_buildDirTileWithTitle),
+                ],
+              ),
+            );
+          }
+          return AnimationLimiter(
+            // we update the limiter key after fetching the metadata of a new entry,
+            // in order to restart the staggered animation of the metadata section
+            key: Key(_loadedMetadataUri.value),
+            child: content,
           );
         },
-        childCount: 1 + metadata.length,
       ),
     );
   }
 
-  Widget _buildDirTileWithoutTitle(MetadataDirectory dir) {
+  Widget _buildDirTileWithoutTitle(_MetadataDirectory dir) {
     return InfoRowGroup(dir.tags, maxValueLength: Constants.infoGroupMaxValueLength);
   }
 
-  Widget _buildDirTileWithTitle(MetadataDirectory dir) {
+  Widget _buildDirTileWithTitle(_MetadataDirectory dir) {
     Widget thumbnail;
     final prefixChildren = <Widget>[];
     switch (dir.name) {
@@ -123,13 +168,43 @@ class metadataSectionSliverState extends State<MetadataSectionSliver> with Autom
     );
   }
 
+  void _onMetadataChanged() {
+    _loadedMetadataUri.value = null;
+    _metadata = [];
+    _getMetadata();
+  }
+
+  Future<void> _getMetadata() async {
+    if (entry == null) return;
+    if (_loadedMetadataUri.value == entry.uri) return;
+    if (isVisible) {
+      final rawMetadata = await MetadataService.getAllMetadata(entry) ?? {};
+      _metadata = rawMetadata.entries.map((dirKV) {
+        final directoryName = dirKV.key as String ?? '';
+        final rawTags = dirKV.value as Map ?? {};
+        final tags = SplayTreeMap.of(Map.fromEntries(rawTags.entries.map((tagKV) {
+          final value = tagKV.value as String ?? '';
+          if (value.isEmpty) return null;
+          final tagName = tagKV.key as String ?? '';
+          return MapEntry(tagName, value);
+        }).where((kv) => kv != null)));
+        return _MetadataDirectory(directoryName, tags);
+      }).toList()
+        ..sort((a, b) => compareAsciiUpperCase(a.name, b.name));
+      _loadedMetadataUri.value = entry.uri;
+    } else {
+      _metadata = [];
+      _loadedMetadataUri.value = null;
+    }
+  }
+
   @override
   bool get wantKeepAlive => true;
 }
 
-class MetadataDirectory {
+class _MetadataDirectory {
   final String name;
   final SplayTreeMap<String, String> tags;
 
-  const MetadataDirectory(this.name, this.tags);
+  const _MetadataDirectory(this.name, this.tags);
 }

lib/widgets/stats/stats.dart

@@ -16,6 +16,7 @@ import 'package:aves/widgets/common/icons.dart';
 import 'package:aves/widgets/stats/filter_table.dart';
 import 'package:charts_flutter/flutter.dart' as charts;
 import 'package:collection/collection.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 import 'package:percent_indicator/linear_percent_indicator.dart';
@@ -262,6 +263,6 @@ class EntryByMimeDatum {
 
   @override
   String toString() {
-    return '[$runtimeType#$hashCode: mimeType=$mimeType, displayText=$displayText, entryCount=$entryCount]';
+    return '[$runtimeType#${shortHash(this)}: mimeType=$mimeType, displayText=$displayText, entryCount=$entryCount]';
   }
 }