rebuild performance review

lib/widgets/collection/collection_grid.dart

@@ -32,12 +32,12 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
 import 'package:provider/provider.dart';
 
-class ThumbnailCollection extends StatefulWidget {
+class CollectionGrid extends StatefulWidget {
   @override
-  _ThumbnailCollectionState createState() => _ThumbnailCollectionState();
+  _CollectionGridState createState() => _CollectionGridState();
 }
 
-class _ThumbnailCollectionState extends State<ThumbnailCollection> {
+class _CollectionGridState extends State<CollectionGrid> {
   TileExtentController _tileExtentController;
 
   @override
@@ -48,54 +48,20 @@ class _ThumbnailCollectionState extends State<ThumbnailCollection> {
       extentMin: 46,
       spacing: 0,
     );
-    return SafeArea(
+    return TileExtentControllerProvider(
-      bottom: false,
+      controller: _tileExtentController,
-      child: TileExtentControllerProvider(
+      child: _CollectionGridContent(),
-        controller: _tileExtentController,
-        child: _ThumbnailCollectionContent(),
-      ),
     );
   }
 }
 
-class _ThumbnailCollectionContent extends StatelessWidget {
+class _CollectionGridContent extends StatelessWidget {
-  final ValueNotifier<double> _appBarHeightNotifier = ValueNotifier(0);
   final ValueNotifier<bool> _isScrollingNotifier = ValueNotifier(false);
-  final GlobalKey _scrollableKey = GlobalKey(debugLabel: 'thumbnail-collection-scrollable');
 
   @override
   Widget build(BuildContext context) {
-    final scrollController = PrimaryScrollController.of(context);
     return Consumer<CollectionLens>(
       builder: (context, collection, child) {
-        final scrollView = AnimationLimiter(
-          child: CollectionScrollView(
-            scrollableKey: _scrollableKey,
-            collection: collection,
-            appBar: CollectionAppBar(
-              appBarHeightNotifier: _appBarHeightNotifier,
-              collection: collection,
-            ),
-            appBarHeightNotifier: _appBarHeightNotifier,
-            isScrollingNotifier: _isScrollingNotifier,
-            scrollController: scrollController,
-          ),
-        );
-
-        final scaler = _ThumbnailGridScaleGestureDetector(
-          scrollableKey: _scrollableKey,
-          appBarHeightNotifier: _appBarHeightNotifier,
-          child: scrollView,
-        );
-
-        final selector = GridSelectionGestureDetector(
-          selectable: AvesApp.mode == AppMode.main,
-          collection: collection,
-          scrollController: scrollController,
-          appBarHeightNotifier: _appBarHeightNotifier,
-          child: scaler,
-        );
-
         final sectionedListLayoutProvider = ValueListenableBuilder<double>(
           valueListenable: context.select<TileExtentController, ValueNotifier<double>>((controller) => controller.extentNotifier),
           builder: (context, tileExtent, child) {
@@ -111,7 +77,11 @@ class _ThumbnailCollectionContent extends StatelessWidget {
                 tileExtent: tileExtent,
                 isScrollingNotifier: _isScrollingNotifier,
               ),
-              child: selector,
+              child: _CollectionSectionedContent(
+                collection: collection,
+                isScrollingNotifier: _isScrollingNotifier,
+                scrollController: PrimaryScrollController.of(context),
+              ),
             );
           },
         );
@@ -121,12 +91,69 @@ class _ThumbnailCollectionContent extends StatelessWidget {
   }
 }
 
-class _ThumbnailGridScaleGestureDetector extends StatelessWidget {
+class _CollectionSectionedContent extends StatefulWidget {
+  final CollectionLens collection;
+  final ValueNotifier<bool> isScrollingNotifier;
+  final ScrollController scrollController;
+
+  const _CollectionSectionedContent({
+    @required this.collection,
+    @required this.isScrollingNotifier,
+    @required this.scrollController,
+  });
+
+  @override
+  _CollectionSectionedContentState createState() => _CollectionSectionedContentState();
+}
+
+class _CollectionSectionedContentState extends State<_CollectionSectionedContent> {
+  CollectionLens get collection => widget.collection;
+
+  ScrollController get scrollController => widget.scrollController;
+
+  final ValueNotifier<double> _appBarHeightNotifier = ValueNotifier(0);
+  final GlobalKey _scrollableKey = GlobalKey(debugLabel: 'thumbnail-collection-scrollable');
+
+  @override
+  Widget build(BuildContext context) {
+    final scrollView = AnimationLimiter(
+      child: _CollectionScrollView(
+        scrollableKey: _scrollableKey,
+        collection: collection,
+        appBar: CollectionAppBar(
+          appBarHeightNotifier: _appBarHeightNotifier,
+          collection: collection,
+        ),
+        appBarHeightNotifier: _appBarHeightNotifier,
+        isScrollingNotifier: widget.isScrollingNotifier,
+        scrollController: scrollController,
+      ),
+    );
+
+    final scaler = _CollectionScaler(
+      scrollableKey: _scrollableKey,
+      appBarHeightNotifier: _appBarHeightNotifier,
+      child: scrollView,
+    );
+
+    final selector = GridSelectionGestureDetector(
+      selectable: AvesApp.mode == AppMode.main,
+      collection: collection,
+      scrollController: scrollController,
+      appBarHeightNotifier: _appBarHeightNotifier,
+      child: scaler,
+    );
+
+    return selector;
+  }
+}
+
+class _CollectionScaler extends StatelessWidget {
   final GlobalKey scrollableKey;
   final ValueNotifier<double> appBarHeightNotifier;
   final Widget child;
 
-  const _ThumbnailGridScaleGestureDetector({
+  const _CollectionScaler({
     @required this.scrollableKey,
     @required this.appBarHeightNotifier,
     @required this.child,
@@ -166,7 +193,7 @@ class _ThumbnailGridScaleGestureDetector extends StatelessWidget {
   }
 }
 
-class CollectionScrollView extends StatefulWidget {
+class _CollectionScrollView extends StatefulWidget {
   final GlobalKey scrollableKey;
   final CollectionLens collection;
   final Widget appBar;
@@ -174,7 +201,7 @@ class CollectionScrollView extends StatefulWidget {
   final ValueNotifier<bool> isScrollingNotifier;
   final ScrollController scrollController;
 
-  const CollectionScrollView({
+  const _CollectionScrollView({
     @required this.scrollableKey,
     @required this.collection,
     @required this.appBar,
@@ -187,7 +214,7 @@ class CollectionScrollView extends StatefulWidget {
   _CollectionScrollViewState createState() => _CollectionScrollViewState();
 }
 
-class _CollectionScrollViewState extends State<CollectionScrollView> {
+class _CollectionScrollViewState extends State<_CollectionScrollView> {
   Timer _scrollMonitoringTimer;
 
   @override
@@ -197,7 +224,7 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
   }
 
   @override
-  void didUpdateWidget(covariant CollectionScrollView oldWidget) {
+  void didUpdateWidget(covariant _CollectionScrollView oldWidget) {
     super.didUpdateWidget(oldWidget);
     _unregisterWidget(oldWidget);
     _registerWidget(widget);
@@ -210,13 +237,13 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
     super.dispose();
   }
 
-  void _registerWidget(CollectionScrollView widget) {
+  void _registerWidget(_CollectionScrollView widget) {
     widget.collection.filterChangeNotifier.addListener(_scrollToTop);
     widget.collection.sortGroupChangeNotifier.addListener(_scrollToTop);
     widget.scrollController.addListener(_onScrollChange);
   }
 
-  void _unregisterWidget(CollectionScrollView widget) {
+  void _unregisterWidget(_CollectionScrollView widget) {
     widget.collection.filterChangeNotifier.removeListener(_scrollToTop);
     widget.collection.sortGroupChangeNotifier.removeListener(_scrollToTop);
     widget.scrollController.removeListener(_onScrollChange);
@@ -228,27 +255,6 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
     return _buildDraggableScrollView(scrollView);
   }
 
-  ScrollView _buildScrollView(Widget appBar, CollectionLens collection) {
-    return CustomScrollView(
-      key: widget.scrollableKey,
-      primary: true,
-      // workaround to prevent scrolling the app bar away
-      // when there is no content and we use `SliverFillRemaining`
-      physics: collection.isEmpty ? NeverScrollableScrollPhysics() : SloppyScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
-      cacheExtent: context.select<TileExtentController, double>((controller) => controller.effectiveExtentMax * 2),
-      slivers: [
-        appBar,
-        collection.isEmpty
-            ? SliverFillRemaining(
-                hasScrollBody: false,
-                child: _buildEmptyCollectionPlaceholder(collection),
-              )
-            : SectionedListSliver<AvesEntry>(),
-        BottomPaddingSliver(),
-      ],
-    );
-  }
-
   Widget _buildDraggableScrollView(ScrollView scrollView) {
     return ValueListenableBuilder<double>(
       valueListenable: widget.appBarHeightNotifier,
@@ -274,6 +280,27 @@ class _CollectionScrollViewState extends State<CollectionScrollView> {
     );
   }
 
+  ScrollView _buildScrollView(Widget appBar, CollectionLens collection) {
+    return CustomScrollView(
+      key: widget.scrollableKey,
+      primary: true,
+      // workaround to prevent scrolling the app bar away
+      // when there is no content and we use `SliverFillRemaining`
+      physics: collection.isEmpty ? NeverScrollableScrollPhysics() : SloppyScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
+      cacheExtent: context.select<TileExtentController, double>((controller) => controller.effectiveExtentMax * 2),
+      slivers: [
+        appBar,
+        collection.isEmpty
+            ? SliverFillRemaining(
+                hasScrollBody: false,
+                child: _buildEmptyCollectionPlaceholder(collection),
+              )
+            : SectionedListSliver<AvesEntry>(),
+        BottomPaddingSliver(),
+      ],
+    );
+  }
+
   Widget _buildEmptyCollectionPlaceholder(CollectionLens collection) {
     return ValueListenableBuilder<SourceState>(
       valueListenable: collection.source.stateNotifier,

lib/widgets/collection/collection_page.dart

@@ -1,5 +1,5 @@
 import 'package:aves/model/source/collection_lens.dart';
-import 'package:aves/widgets/collection/thumbnail_collection.dart';
+import 'package:aves/widgets/collection/collection_grid.dart';
 import 'package:aves/widgets/common/basic/insets.dart';
 import 'package:aves/widgets/common/behaviour/double_back_pop.dart';
 import 'package:aves/widgets/common/providers/media_query_data_provider.dart';
@@ -42,9 +42,12 @@ class _CollectionPageState extends State<CollectionPage> {
           },
           child: DoubleBackPopScope(
             child: GestureAreaProtectorStack(
-              child: ChangeNotifierProvider<CollectionLens>.value(
+              child: SafeArea(
-                value: collection,
+                bottom: false,
-                child: ThumbnailCollection(),
+                child: ChangeNotifierProvider<CollectionLens>.value(
+                  value: collection,
+                  child: CollectionGrid(),
+                ),
               ),
             ),
           ),

lib/widgets/filter_grids/album_pick.dart

@@ -58,21 +58,21 @@ class _AlbumPickPageState extends State<AlbumPickPage> {
         return StreamBuilder(
           stream: source.eventBus.on<AlbumsChangedEvent>(),
           builder: (context, snapshot) => FilterGridPage<AlbumFilter>(
+            settingsRouteKey: AlbumListPage.routeName,
             appBar: appBar,
+            appBarHeight: AlbumPickAppBar.preferredHeight,
             filterSections: AlbumListPage.getAlbumEntries(context, source),
             showHeaders: settings.albumGroupFactor != AlbumChipGroupFactor.none,
+            queryNotifier: _queryNotifier,
             applyQuery: (filters, query) {
               if (query == null || query.isEmpty) return filters;
               query = query.toUpperCase();
               return filters.where((item) => item.filter.uniqueName.toUpperCase().contains(query)).toList();
             },
-            queryNotifier: _queryNotifier,
             emptyBuilder: () => EmptyContent(
               icon: AIcons.album,
               text: context.l10n.albumEmpty,
             ),
-            settingsRouteKey: AlbumListPage.routeName,
-            appBarHeight: AlbumPickAppBar.preferredHeight,
             onTap: (filter) => Navigator.pop<String>(context, (filter as AlbumFilter)?.album),
           ),
         );

lib/widgets/filter_grids/common/filter_grid_page.dart

@@ -29,27 +29,27 @@ import 'package:provider/provider.dart';
 typedef QueryTest<T extends CollectionFilter> = Iterable<FilterGridItem<T>> Function(Iterable<FilterGridItem<T>> filters, String query);
 
 class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
+  final String settingsRouteKey;
   final Widget appBar;
+  final double appBarHeight;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
   final bool showHeaders;
   final ValueNotifier<String> queryNotifier;
-  final Widget Function() emptyBuilder;
-  final String settingsRouteKey;
-  final double appBarHeight;
   final QueryTest<T> applyQuery;
+  final Widget Function() emptyBuilder;
   final FilterCallback onTap;
   final OffsetFilterCallback onLongPress;
 
   const FilterGridPage({
     Key key,
+    this.settingsRouteKey,
     @required this.appBar,
+    this.appBarHeight = kToolbarHeight,
     @required this.filterSections,
-    this.showHeaders = false,
+    @required this.showHeaders,
     @required this.queryNotifier,
     this.applyQuery,
     @required this.emptyBuilder,
-    this.settingsRouteKey,
-    this.appBarHeight = kToolbarHeight,
     @required this.onTap,
     this.onLongPress,
   }) : super(key: key);
@@ -64,24 +64,17 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
           child: GestureAreaProtectorStack(
             child: SafeArea(
               bottom: false,
-              child: TileExtentControllerProvider(
+              child: FilterGrid<T>(
-                controller: TileExtentController(
+                settingsRouteKey: settingsRouteKey,
-                  settingsRouteKey: settingsRouteKey ?? context.currentRouteName,
+                appBar: appBar,
-                  columnCountDefault: 2,
+                appBarHeight: appBarHeight,
-                  extentMin: 60,
+                filterSections: filterSections,
-                  spacing: 8,
+                showHeaders: showHeaders,
-                ),
+                queryNotifier: queryNotifier,
-                child: _FilterGridPageContent<T>(
+                applyQuery: applyQuery,
-                  appBar: appBar,
+                emptyBuilder: emptyBuilder,
-                  filterSections: filterSections,
+                onTap: onTap,
-                  showHeaders: showHeaders,
+                onLongPress: onLongPress,
-                  queryNotifier: queryNotifier,
-                  applyQuery: applyQuery,
-                  emptyBuilder: emptyBuilder,
-                  appBarHeight: appBarHeight,
-                  onTap: onTap,
-                  onLongPress: onLongPress,
-                ),
               ),
             ),
           ),
@@ -93,7 +86,65 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
   }
 }
 
-class _FilterGridPageContent<T extends CollectionFilter> extends StatelessWidget {
+class FilterGrid<T extends CollectionFilter> extends StatefulWidget {
+  final String settingsRouteKey;
+  final Widget appBar;
+  final double appBarHeight;
+  final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
+  final bool showHeaders;
+  final ValueNotifier<String> queryNotifier;
+  final QueryTest<T> applyQuery;
+  final Widget Function() emptyBuilder;
+  final FilterCallback onTap;
+  final OffsetFilterCallback onLongPress;
+
+  const FilterGrid({
+    Key key,
+    @required this.settingsRouteKey,
+    @required this.appBar,
+    @required this.appBarHeight,
+    @required this.filterSections,
+    @required this.showHeaders,
+    @required this.queryNotifier,
+    @required this.applyQuery,
+    @required this.emptyBuilder,
+    @required this.onTap,
+    @required this.onLongPress,
+  }) : super(key: key);
+
+  @override
+  _FilterGridState createState() => _FilterGridState<T>();
+}
+
+class _FilterGridState<T extends CollectionFilter> extends State<FilterGrid<T>> {
+  TileExtentController _tileExtentController;
+
+  @override
+  Widget build(BuildContext context) {
+    _tileExtentController ??= TileExtentController(
+      settingsRouteKey: widget.settingsRouteKey ?? context.currentRouteName,
+      columnCountDefault: 2,
+      extentMin: 60,
+      spacing: 8,
+    );
+    return TileExtentControllerProvider(
+      controller: _tileExtentController,
+      child: _FilterGridContent<T>(
+        appBar: widget.appBar,
+        appBarHeight: widget.appBarHeight,
+        filterSections: widget.filterSections,
+        showHeaders: widget.showHeaders,
+        queryNotifier: widget.queryNotifier,
+        applyQuery: widget.applyQuery,
+        emptyBuilder: widget.emptyBuilder,
+        onTap: widget.onTap,
+        onLongPress: widget.onLongPress,
+      ),
+    );
+  }
+}
+
+class _FilterGridContent<T extends CollectionFilter> extends StatelessWidget {
   final Widget appBar;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
   final bool showHeaders;
@@ -105,15 +156,15 @@ class _FilterGridPageContent<T extends CollectionFilter> extends StatelessWidget
 
   final ValueNotifier<double> _appBarHeightNotifier = ValueNotifier(0);
 
-  _FilterGridPageContent({
+  _FilterGridContent({
     Key key,
     @required this.appBar,
+    @required double appBarHeight,
     @required this.filterSections,
     @required this.showHeaders,
     @required this.queryNotifier,
     @required this.applyQuery,
     @required this.emptyBuilder,
-    @required double appBarHeight,
     @required this.onTap,
     @required this.onLongPress,
   }) : super(key: key) {
@@ -166,7 +217,7 @@ class _FilterGridPageContent<T extends CollectionFilter> extends StatelessWidget
                   ),
                 );
               },
-              child: _SectionedContent<T>(
+              child: _FilterSectionedContent<T>(
                 appBar: appBar,
                 appBarHeightNotifier: _appBarHeightNotifier,
                 visibleFilterSections: visibleFilterSections,
@@ -182,14 +233,14 @@ class _FilterGridPageContent<T extends CollectionFilter> extends StatelessWidget
   }
 }
 
-class _SectionedContent<T extends CollectionFilter> extends StatefulWidget {
+class _FilterSectionedContent<T extends CollectionFilter> extends StatefulWidget {
   final Widget appBar;
   final ValueNotifier<double> appBarHeightNotifier;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> visibleFilterSections;
   final Widget Function() emptyBuilder;
   final ScrollController scrollController;
 
-  const _SectionedContent({
+  const _FilterSectionedContent({
     @required this.appBar,
     @required this.appBarHeightNotifier,
     @required this.visibleFilterSections,
@@ -198,10 +249,10 @@ class _SectionedContent<T extends CollectionFilter> extends StatefulWidget {
   });
 
   @override
-  _SectionedContentState createState() => _SectionedContentState<T>();
+  _FilterSectionedContentState createState() => _FilterSectionedContentState<T>();
 }
 
-class _SectionedContentState<T extends CollectionFilter> extends State<_SectionedContent<T>> {
+class _FilterSectionedContentState<T extends CollectionFilter> extends State<_FilterSectionedContent<T>> {
   Widget get appBar => widget.appBar;
 
   ValueNotifier<double> get appBarHeightNotifier => widget.appBarHeightNotifier;
@@ -220,6 +271,27 @@ class _SectionedContentState<T extends CollectionFilter> extends State<_Sectione
     WidgetsBinding.instance.addPostFrameCallback((_) => _checkInitHighlight());
   }
 
+  @override
+  Widget build(BuildContext context) {
+    final scrollView = AnimationLimiter(
+      child: _FilterScrollView<T>(
+        scrollableKey: _scrollableKey,
+        appBar: appBar,
+        appBarHeightNotifier: appBarHeightNotifier,
+        emptyBuilder: emptyBuilder,
+        scrollController: scrollController,
+      ),
+    );
+
+    final scaler = _FilterScaler<T>(
+      scrollableKey: _scrollableKey,
+      appBarHeightNotifier: appBarHeightNotifier,
+      child: scrollView,
+    );
+
+    return scaler;
+  }
+
   Future<void> _checkInitHighlight() async {
     final highlightInfo = context.read<HighlightInfo>();
     final filter = highlightInfo.clear();
@@ -252,13 +324,25 @@ class _SectionedContentState<T extends CollectionFilter> extends State<_Sectione
       );
     }
   }
+}
+
+class _FilterScaler<T extends CollectionFilter> extends StatelessWidget {
+  final GlobalKey scrollableKey;
+  final ValueNotifier<double> appBarHeightNotifier;
+  final Widget child;
+
+  const _FilterScaler({
+    @required this.scrollableKey,
+    @required this.appBarHeightNotifier,
+    @required this.child,
+  });
 
   @override
   Widget build(BuildContext context) {
     final pinnedFilters = settings.pinnedFilters;
     final tileSpacing = context.select<TileExtentController, double>((controller) => controller.spacing);
     return GridScaleGestureDetector<FilterGridItem<T>>(
-      scrollableKey: _scrollableKey,
+      scrollableKey: scrollableKey,
       appBarHeightNotifier: appBarHeightNotifier,
       gridBuilder: (center, extent, child) => CustomPaint(
         painter: GridPainter(
@@ -283,11 +367,31 @@ class _SectionedContentState<T extends CollectionFilter> extends State<_Sectione
         return sectionedListLayout.getTileRect(item) ?? Rect.zero;
       },
       onScaled: (item) => context.read<HighlightInfo>().set(item.filter),
-      child: AnimationLimiter(
+      child: child,
-        child: _buildDraggableScrollView(_buildScrollView(context, visibleFilterSections.isEmpty)),
-      ),
     );
   }
+}
+
+class _FilterScrollView<T extends CollectionFilter> extends StatelessWidget {
+  final GlobalKey scrollableKey;
+  final Widget appBar;
+  final ValueNotifier<double> appBarHeightNotifier;
+  final Widget Function() emptyBuilder;
+  final ScrollController scrollController;
+
+  const _FilterScrollView({
+    @required this.scrollableKey,
+    @required this.appBar,
+    @required this.appBarHeightNotifier,
+    @required this.emptyBuilder,
+    @required this.scrollController,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final scrollView = _buildScrollView(context);
+    return _buildDraggableScrollView(scrollView);
+  }
 
   Widget _buildDraggableScrollView(ScrollView scrollView) {
     return Selector<MediaQueryData, double>(
@@ -310,31 +414,30 @@ class _SectionedContentState<T extends CollectionFilter> extends State<_Sectione
     );
   }
 
-  ScrollView _buildScrollView(BuildContext context, bool empty) {
+  ScrollView _buildScrollView(BuildContext context) {
-    Widget content;
-    if (empty) {
-      content = SliverFillRemaining(
-        hasScrollBody: false,
-        child: Selector<MediaQueryData, double>(
-          selector: (context, mq) => mq.effectiveBottomPadding,
-          builder: (context, mqPaddingBottom, child) {
-            return Padding(
-              padding: EdgeInsets.only(bottom: mqPaddingBottom),
-              child: emptyBuilder(),
-            );
-          },
-        ),
-      );
-    } else {
-      content = SectionedListSliver<FilterGridItem<T>>();
-    }
-
     return CustomScrollView(
-      key: _scrollableKey,
+      key: scrollableKey,
       controller: scrollController,
       slivers: [
         appBar,
-        content,
+        Selector<SectionedListLayout<FilterGridItem<T>>, bool>(
+            selector: (context, layout) => layout.sections.isEmpty,
+            builder: (context, empty, child) {
+              return empty
+                  ? SliverFillRemaining(
+                      hasScrollBody: false,
+                      child: Selector<MediaQueryData, double>(
+                        selector: (context, mq) => mq.effectiveBottomPadding,
+                        builder: (context, mqPaddingBottom, child) {
+                          return Padding(
+                            padding: EdgeInsets.only(bottom: mqPaddingBottom),
+                            child: emptyBuilder(),
+                          );
+                        },
+                      ),
+                    )
+                  : SectionedListSliver<FilterGridItem<T>>();
+            }),
         BottomPaddingSliver(),
       ],
     );