⚡️ Improve AssetPickerProvider.paths (#473)

Author: AlexV525

CHANGELOG.md

@@ -6,6 +6,12 @@ that can be found in the LICENSE file. -->
 
 See the [Migration Guide](guides/migration_guide.md) for the details of breaking changes between versions.
 
+## 8.6.3
+
+### Improvements
+
+- Improve `AssetPickerProvider.paths`.
+
 ## 8.6.2
 
 ### Improvements

example/lib/customs/pickers/directory_file_asset_picker.dart

@@ -290,15 +290,14 @@ class FileAssetPickerProvider extends AssetPickerProvider<File, Directory> {
   @override
   Future<void> getPaths() async {
     currentAssets = <File>[];
-    paths.clear();
     final Directory directory = await getApplicationDocumentsDirectory();
     final PathWrapper<Directory> wrapper = PathWrapper<Directory>(
       path: directory,
       thumbnailData: await getThumbnailFromPath(
         PathWrapper<Directory>(path: directory),
       ),
     );
-    paths.add(wrapper);
+    paths = [wrapper];
     currentPath = wrapper;
   }
 
@@ -315,6 +314,11 @@ class FileAssetPickerProvider extends AssetPickerProvider<File, Directory> {
     }
     hasAssetsToDisplay = currentAssets.isNotEmpty;
     totalAssetsCount = currentAssets.length;
+    isAssetsEmpty = totalAssetsCount == 0;
+    final PathWrapper<Directory> wrapper = currentPath!;
+    if (wrapper.assetCount == null) {
+      currentPath = currentPath!.copyWith(assetCount: totalAssetsCount);
+    }
   }
 
   @override
@@ -522,12 +526,8 @@ class FileAssetPickerBuilder
       children: <Widget>[
         Positioned.fill(
           child: Selector<FileAssetPickerProvider, bool>(
-            selector: (
-              _,
-              FileAssetPickerProvider p,
-            ) =>
-                p.hasAssetsToDisplay,
-            builder: (_, bool hasAssetsToDisplay, __) {
+            selector: (_, FileAssetPickerProvider p) => p.hasAssetsToDisplay,
+            builder: (BuildContext context, bool hasAssetsToDisplay, __) {
               return AnimatedSwitcher(
                 duration: switchingPathDuration,
                 child: hasAssetsToDisplay
@@ -607,7 +607,7 @@ class FileAssetPickerBuilder
         delegate: SliverChildBuilderDelegate(
           (_, int index) => Builder(
             builder: (BuildContext c) {
-              if (isAppleOS(context)) {
+              if (isAppleOS(c)) {
                 if (index < placeholderCount) {
                   return const SizedBox.shrink();
                 }
@@ -663,7 +663,7 @@ class FileAssetPickerBuilder
             child: Selector<FileAssetPickerProvider, List<File>>(
               selector: (_, FileAssetPickerProvider provider) =>
                   provider.currentAssets,
-              builder: (_, List<File> assets, __) => CustomScrollView(
+              builder: (context, List<File> assets, __) => CustomScrollView(
                 physics: const AlwaysScrollableScrollPhysics(),
                 controller: gridScrollController,
                 anchor: isAppleOS(context) ? anchor : 0,
@@ -676,7 +676,7 @@ class FileAssetPickerBuilder
                             appBarPreferredSize!.height,
                       ),
                     ),
-                  sliverGrid(_, assets),
+                  sliverGrid(context, assets),
                   // Ignore the gap when the [anchor] is not equal to 1.
                   if (isAppleOS(context) && anchor == 1)
                     SliverToBoxAdapter(

example/pubspec.yaml

@@ -1,6 +1,6 @@
 name: wechat_assets_picker_demo
 description: The demo project for the wechat_assets_picker package.
-version: 8.6.2+42
+version: 8.6.3+43
 publish_to: none
 
 environment:

lib/src/delegates/asset_picker_builder_delegate.dart

@@ -832,7 +832,7 @@ class DefaultAssetPickerBuilderDelegate
           ..hasAssetsToDisplay = false
           ..isAssetsEmpty = true
           ..totalAssetsCount = 0
-          ..paths.clear();
+          ..paths = [];
         return;
       }
     }

lib/src/provider/asset_picker_provider.dart

@@ -15,7 +15,7 @@ import '../delegates/sort_path_delegate.dart';
 import '../internal/singleton.dart';
 import '../models/path_wrapper.dart';
 
-/// [ChangeNotifier] for assets picker.
+/// Helps the assets picker to manage [Path]s and [Asset]s.
 ///
 /// The provider maintain all methods that control assets and paths.
 /// By extending it you can customize how you can get all assets or paths,
@@ -29,7 +29,7 @@ abstract class AssetPickerProvider<Asset, Path> extends ChangeNotifier {
     List<Asset>? selectedAssets,
   })  : assert(maxAssets > 0, 'maxAssets must be greater than 0.'),
         assert(pageSize > 0, 'pageSize must be greater than 0.'),
-        _previousSelectedAssets =
+        previousSelectedAssets =
             selectedAssets?.toList(growable: false) ?? List<Asset>.empty(),
         _selectedAssets =
             selectedAssets?.toList() ?? List<Asset>.empty(growable: true);
@@ -48,6 +48,10 @@ abstract class AssetPickerProvider<Asset, Path> extends ChangeNotifier {
   /// 路径选择器中缩略图的大小
   final ThumbnailSize pathThumbnailSize;
 
+  /// Selected assets before the picker starts picking.
+  /// 选择器开始选择前已选中的资源
+  final List<Asset> previousSelectedAssets;
+
   /// Clear all fields when dispose.
   /// 销毁时重置所有内容
   @override
@@ -127,15 +131,18 @@ abstract class AssetPickerProvider<Asset, Path> extends ChangeNotifier {
     notifyListeners();
   }
 
-  /// Map for all path entity.
-  /// 所有包含资源的路径里列表
-  ///
-  /// Using [Map] in order to save the thumbnail data
-  /// for the first asset under the path.
-  /// 使用 [Map] 来保存路径下第一个资源的缩略图数据
+  /// List for all path entity wrapped by [PathWrapper].
+  /// 所有资源路径的列表，以 [PathWrapper] 包装
   List<PathWrapper<Path>> get paths => _paths;
   List<PathWrapper<Path>> _paths = <PathWrapper<Path>>[];
 
+  set paths(List<PathWrapper<Path>> value) {
+    if (value != _paths) {
+      _paths = value;
+      notifyListeners();
+    }
+  }
+
   /// Set thumbnail [data] for the specific [path].
   /// 为指定的路径设置缩略图数据
   void setPathThumbnail(Path path, Uint8List? data) {
@@ -177,11 +184,6 @@ abstract class AssetPickerProvider<Asset, Path> extends ChangeNotifier {
     notifyListeners();
   }
 
-  /// Selected assets before the picker starts picking.
-  /// 选择器开始选择前已选中的资源
-  List<Asset> get previousSelectedAssets => _previousSelectedAssets;
-  final List<Asset> _previousSelectedAssets;
-
   /// Selected assets.
   /// 已选中的资源
   List<Asset> get selectedAssets => _selectedAssets;
@@ -232,6 +234,8 @@ abstract class AssetPickerProvider<Asset, Path> extends ChangeNotifier {
   }
 }
 
+/// The default implementation of the [AssetPickerProvider] for the picker.
+/// The `Asset` is [AssetEntity], and the `Path` is [AssetPathEntity].
 class DefaultAssetPickerProvider
     extends AssetPickerProvider<AssetEntity, AssetPathEntity> {
   DefaultAssetPickerProvider({

pubspec.yaml

@@ -1,5 +1,5 @@
 name: wechat_assets_picker
-version: 8.6.2
+version: 8.6.3
 description: |
   An image picker (also with videos and audio)
   for Flutter projects based on WeChat's UI,