⚡️ Split assets fetching into separate steps (#596)

### Changes
1. Change the fetching steps to loading the first album first, then the
others.
2. Use `AdvancedCustomFilter` by default to order items in desc without
extra search queries to decrease the query complexity.

- Resolves #496
- Resolves #526
- Resolves #547

CHANGELOG.md

@@ -18,8 +18,8 @@ that can be found in the LICENSE file. -->
 - Support limited permission displays on Android.
 - Improves the limited overlay padding on Android.
 - Adds permission request lock for the picker state.
-
-## 9.0.5
+- Speeding up by splitting asset loading into separate steps.
+- Speeding up using `AdvancedCustomFilter` rather than `FilterOptionGroup` by default.
 
 ### Fixes
 

lib/src/provider/asset_picker_provider.dart

@@ -273,7 +273,10 @@ class DefaultAssetPickerProvider
   }) {
     Singleton.sortPathDelegate = sortPathDelegate ?? SortPathDelegate.common;
     // Call [getAssetList] with route duration when constructing.
-    Future<void>.delayed(initializeDelayDuration, getPaths);
+    Future<void>.delayed(initializeDelayDuration, () async {
+      await getPaths(onlyAll: true);
+      await getPaths(onlyAll: false);
+    });
   }
 
   @visibleForTesting
@@ -326,41 +329,40 @@ class DefaultAssetPickerProvider
   }
 
   @override
-  Future<void> getPaths() async {
+  Future<void> getPaths({bool onlyAll = false}) async {
     final PMFilter options;
-    final PMFilter? fog = filterOptions;
-    if (fog is FilterOptionGroup?) {
-      // Initial base options.
-      // Enable need title for audios to get proper display.
-      final FilterOptionGroup newOptions = FilterOptionGroup(
+    final fog = filterOptions;
+    if (fog == null) {
+      options = AdvancedCustomFilter(
+        orderBy: [OrderByItem.desc(CustomColumns.base.createDate)],
+      );
+    } else if (fog is FilterOptionGroup) {
+      final newOptions = FilterOptionGroup(
         imageOption: const FilterOption(
           sizeConstraint: SizeConstraint(ignoreSize: true),
         ),
         audioOption: const FilterOption(
+          // Enable title for audios to get proper display.
           needTitle: true,
           sizeConstraint: SizeConstraint(ignoreSize: true),
         ),
         containsPathModified: sortPathsByModifiedDate,
         createTimeCond: DateTimeCond.def().copyWith(ignore: true),
         updateTimeCond: DateTimeCond.def().copyWith(ignore: true),
       );
-      // Merge user's filter options into base options if it's not null.
-      if (fog != null) {
-        newOptions.merge(fog);
-      }
+      newOptions.merge(fog);
       options = newOptions;
     } else {
       options = fog;
     }
 
-    final List<AssetPathEntity> list = await PhotoManager.getAssetPathList(
+    final list = await PhotoManager.getAssetPathList(
       type: requestType,
       filterOption: options,
+      onlyAll: onlyAll,
     );
 
-    _paths = list
-        .map((AssetPathEntity p) => PathWrapper<AssetPathEntity>(path: p))
-        .toList();
+    _paths = list.map((p) => PathWrapper<AssetPathEntity>(path: p)).toList();
     // Sort path using sort path delegate.
     Singleton.sortPathDelegate.sort(_paths);
     // Use sync method to avoid unnecessary wait.
@@ -373,17 +375,19 @@ class DefaultAssetPickerProvider
       _currentPath ??= _paths.first;
     }
 
-    await getAssetsFromCurrentPath();
+    if (onlyAll) {
+      await getAssetsFromCurrentPath();
+    }
   }
 
   Completer<void>? _getAssetsFromPathCompleter;
 
   @override
   Future<void> getAssetsFromPath([int? page, AssetPathEntity? path]) {
     Future<void> run() async {
-      final int currentPage = page ?? currentAssetsListPage;
-      final AssetPathEntity currentPath = path ?? this.currentPath!.path;
-      final List<AssetEntity> list = await currentPath.getAssetListPaged(
+      final currentPage = page ?? currentAssetsListPage;
+      final currentPath = path ?? this.currentPath!.path;
+      final list = await currentPath.getAssetListPaged(
         page: currentPage,
         size: pageSize,
       );

lib/src/widget/asset_picker.dart

@@ -3,6 +3,7 @@
 // in the LICENSE file.
 
 import 'dart:async';
+import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
@@ -121,8 +122,12 @@ class AssetPickerState<Asset, Path> extends State<AssetPicker<Asset, Path>>
     super.didChangeAppLifecycleState(state);
     if (state == AppLifecycleState.resumed) {
       requestPermission().then((ps) {
-        if (mounted) {
-          widget.builder.permission.value = ps;
+        if (!mounted) {
+          return;
+        }
+        widget.builder.permission.value = ps;
+        if (ps == PermissionState.limited && Platform.isAndroid) {
+          _onLimitedAssetsUpdated(const MethodCall(''));
         }
       });
     }