🐛 Unify indicators usage to avoid accidentally indicator switching. (#344)

Author: AlexV525

CHANGELOG.md

@@ -16,6 +16,10 @@ To know more about breaking changes, see [Migration Guide][].
 - Prevent race condition with paths. (#342)
 - Expose `sortPathsByModifiedDate`. (#343)
 
+### Fixes
+
+- Unify indicators usage to avoid accidentally indicator switching. (#344)
+
 ## 7.3.2
 
 ### Improvements

example/lib/customs/pickers/directory_file_asset_picker.dart

@@ -540,6 +540,29 @@ class FileAssetPickerBuilder
     );
   }
 
+  @override
+  Widget loadingIndicator(BuildContext context) {
+    return Selector<FileAssetPickerProvider, bool>(
+      selector: (_, FileAssetPickerProvider p) => p.isAssetsEmpty,
+      builder: (BuildContext context, bool isAssetsEmpty, Widget? w) {
+        if (loadingIndicatorBuilder != null) {
+          return loadingIndicatorBuilder!(context, isAssetsEmpty);
+        }
+        return Center(child: isAssetsEmpty ? emptyIndicator(context) : w);
+      },
+      child: Center(
+        child: SizedBox.fromSize(
+          size: Size.square(Screens.width / gridCount / 3),
+          child: CircularProgressIndicator(
+            valueColor: AlwaysStoppedAnimation<Color>(
+              theme.iconTheme.color ?? Colors.grey,
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
   @override
   Widget assetsGridBuilder(BuildContext context) {
     int totalCount = provider.currentAssets.length;
@@ -770,31 +793,6 @@ class FileAssetPickerBuilder
     return RepaintBoundary(child: Image.file(asset, fit: BoxFit.cover));
   }
 
-  @override
-  Widget loadingIndicator(BuildContext context) {
-    return Center(
-      child: Selector<FileAssetPickerProvider, bool>(
-        selector: (_, FileAssetPickerProvider p) => p.isAssetsEmpty,
-        builder: (_, bool isAssetsEmpty, __) {
-          if (isAssetsEmpty) {
-            return Text(textDelegate.emptyList);
-          } else {
-            return Center(
-              child: SizedBox.fromSize(
-                size: Size.square(Screens.width / gridCount / 3),
-                child: CircularProgressIndicator(
-                  valueColor: AlwaysStoppedAnimation<Color>(
-                    theme.iconTheme.color ?? Colors.grey,
-                  ),
-                ),
-              ),
-            );
-          }
-        },
-      ),
-    );
-  }
-
   @override
   Widget pathEntityListBackdrop(BuildContext context) {
     return ValueListenableBuilder<bool>(

example/pubspec.yaml

@@ -1,6 +1,6 @@
 name: wechat_assets_picker_demo
 description: The demo project for the wechat_assets_picker package.
-version: 8.0.0+20
+version: 8.0.0+21
 publish_to: none
 
 environment:

lib/src/delegates/asset_picker_builder_delegate.dart

@@ -359,6 +359,16 @@ abstract class AssetPickerBuilderDelegate<Asset, Path> {
   /// Android设备的选择器布局
   Widget androidLayout(BuildContext context);
 
+  /// Loading indicator.
+  /// 加载指示器
+  ///
+  /// Subclasses need to implement this due to the generic type limitation, and
+  /// not all delegates use [AssetPickerProvider].
+  ///
+  /// See also:
+  /// - [DefaultAssetPickerBuilderDelegate.loadingIndicator] as an example.
+  Widget loadingIndicator(BuildContext context);
+
   /// GIF image type indicator.
   /// GIF 类型图片指示
   Widget gifIndicator(BuildContext context, Asset asset) {
@@ -414,29 +424,8 @@ abstract class AssetPickerBuilderDelegate<Asset, Path> {
     );
   }
 
-  /// Loading indicator.
-  /// 加载指示器
-  Widget loadingIndicator(BuildContext context) {
-    return Center(
-      child: Selector<AssetPickerProvider<Asset, Path>, bool>(
-        selector: (_, AssetPickerProvider<Asset, Path> p) => p.isAssetsEmpty,
-        builder: (BuildContext c, bool isAssetsEmpty, Widget? w) {
-          if (loadingIndicatorBuilder != null) {
-            return loadingIndicatorBuilder!(c, isAssetsEmpty);
-          }
-          if (isAssetsEmpty) {
-            return emptyIndicator(context);
-          }
-          return w!;
-        },
-        child: PlatformProgressIndicator(
-          color: theme.iconTheme.color,
-          size: context.mediaQuery.size.width / gridCount / 3,
-        ),
-      ),
-    );
-  }
-
+  /// Indicator when no assets were found from the current path.
+  /// 当前目录下无资源的显示
   Widget emptyIndicator(BuildContext context) {
     return ScaleText(
       textDelegate.emptyList,
@@ -1022,6 +1011,23 @@ class DefaultAssetPickerBuilderDelegate
     );
   }
 
+  @override
+  Widget loadingIndicator(BuildContext context) {
+    return Selector<DefaultAssetPickerProvider, bool>(
+      selector: (_, DefaultAssetPickerProvider p) => p.isAssetsEmpty,
+      builder: (BuildContext context, bool isAssetsEmpty, Widget? w) {
+        if (loadingIndicatorBuilder != null) {
+          return loadingIndicatorBuilder!(context, isAssetsEmpty);
+        }
+        return Center(child: isAssetsEmpty ? emptyIndicator(context) : w);
+      },
+      child: PlatformProgressIndicator(
+        color: theme.iconTheme.color,
+        size: context.mediaQuery.size.width / gridCount / 3,
+      ),
+    );
+  }
+
   @override
   Widget assetsGridBuilder(BuildContext context) {
     return Selector<DefaultAssetPickerProvider, PathWrapper<AssetPathEntity>?>(
@@ -1048,8 +1054,7 @@ class DefaultAssetPickerBuilderDelegate
           specialItem = null;
         }
         if (totalCount == 0 && specialItem == null) {
-          return loadingIndicatorBuilder?.call(context, true) ??
-              loadingIndicator(context);
+          return loadingIndicator(context);
         }
         // Then we use the [totalCount] to calculate placeholders we need.
         final int placeholderCount;
@@ -1536,24 +1541,6 @@ class DefaultAssetPickerBuilderDelegate
     );
   }
 
-  @override
-  Widget loadingIndicator(BuildContext context) {
-    return Center(
-      child: Selector<DefaultAssetPickerProvider, bool>(
-        selector: (_, DefaultAssetPickerProvider p) => p.isAssetsEmpty,
-        builder: (BuildContext context, bool isAssetsEmpty, __) {
-          if (isAssetsEmpty) {
-            return emptyIndicator(context);
-          }
-          return PlatformProgressIndicator(
-            color: theme.iconTheme.color,
-            size: context.mediaQuery.size.width / gridCount / 3,
-          );
-        },
-      ),
-    );
-  }
-
   /// While the picker is switching path, this will displayed.
   /// If the user tapped on it, it'll collapse the list widget.
   ///