feat: grid jump to index (#1004)

lib/pages/dynamics_create/view.dart

@@ -595,7 +595,7 @@ class _CreateDynPanelState extends CommonRichTextPubPageState<CreateDynPanel> {
       height: height,
       child: GridView(
         padding: const EdgeInsets.only(left: 12, bottom: 12, right: 12),
-        gridDelegate: const SliverGridDelegateWithExtentAndRatio(
+        gridDelegate: SliverGridDelegateWithExtentAndRatio(
           maxCrossAxisExtent: 65,
           mainAxisSpacing: 12,
           crossAxisSpacing: 12,

lib/pages/member_video/view.dart

@@ -42,6 +42,8 @@ class _MemberVideoState extends State<MemberVideo>
   @override
   bool get wantKeepAlive => true;
 
+  late final gridDelegate = Grid.videoCardHDelegate(context);
+
   late final _controller = Get.put(
     MemberVideoCtr(
       type: widget.type,
@@ -89,12 +91,29 @@ class _MemberVideoState extends State<MemberVideo>
                       top: false,
                       left: false,
                       child: FloatingActionButton.extended(
-                        onPressed: () => _controller
+                        onPressed: () {
+                          final fromViewAid = _controller.fromViewAid;
+                          _controller
                             ..isLocating.value = true
-                          ..lastAid = _controller.fromViewAid
+                            ..lastAid = fromViewAid;
+                          final locatedIndex = _controller
+                              .loadingState
+                              .value
+                              .dataOrNull
+                              ?.indexWhere((i) => i.param == fromViewAid);
+                          if (locatedIndex == null || locatedIndex == -1) {
+                            _controller
                               ..page = 0
                               ..loadingState.value = LoadingState.loading()
-                          ..queryData(),
+                              ..queryData();
+                          } else {
+                            PrimaryScrollController.of(context).jumpTo(
+                              gridDelegate.layoutCache!
+                                  .getGeometryForChildIndex(locatedIndex)
+                                  .scrollOffset,
+                            );
+                          }
+                        },
                         label: const Text('定位至上次观看'),
                       ),
                     ),
@@ -217,7 +236,7 @@ class _MemberVideoState extends State<MemberVideo>
                     ),
                   ),
                   SliverGrid(
-                    gridDelegate: Grid.videoCardHDelegate(context),
+                    gridDelegate: gridDelegate,
                     delegate: SliverChildBuilderDelegate(
                       (context, index) {
                         if (widget.type != ContributeType.season &&

lib/pages/video/reply_new/view.dart

@@ -301,7 +301,7 @@ class _ReplyPageState extends CommonRichTextPubPageState<ReplyPage> {
       height: height,
       child: GridView(
         padding: const EdgeInsets.only(left: 12, bottom: 12, right: 12),
-        gridDelegate: const SliverGridDelegateWithExtentAndRatio(
+        gridDelegate: SliverGridDelegateWithExtentAndRatio(
           maxCrossAxisExtent: 65,
           mainAxisSpacing: 12,
           crossAxisSpacing: 12,

lib/utils/grid.dart

@@ -26,7 +26,7 @@ class SliverGridDelegateWithExtentAndRatio extends SliverGridDelegate {
   /// The [maxCrossAxisExtent], [mainAxisExtent], [mainAxisSpacing],
   /// and [crossAxisSpacing] arguments must not be negative.
   /// The [childAspectRatio] argument must be greater than zero.
-  const SliverGridDelegateWithExtentAndRatio({
+  SliverGridDelegateWithExtentAndRatio({
     required this.maxCrossAxisExtent,
     this.mainAxisSpacing = 0.0,
     this.crossAxisSpacing = 0.0,
@@ -76,9 +76,13 @@ class SliverGridDelegateWithExtentAndRatio extends SliverGridDelegate {
     return true;
   }
 
+  SliverGridLayout? layoutCache;
+
   @override
   SliverGridLayout getLayout(SliverConstraints constraints) {
+    // invoked before each frame
     assert(_debugAssertIsValid(constraints.crossAxisExtent));
+    if (layoutCache != null) return layoutCache!;
     int crossAxisCount =
         ((constraints.crossAxisExtent - crossAxisSpacing) /
                 (maxCrossAxisExtent + crossAxisSpacing))
@@ -95,7 +99,7 @@ class SliverGridDelegateWithExtentAndRatio extends SliverGridDelegate {
       minHeight,
       childCrossAxisExtent / childAspectRatio + mainAxisExtent,
     );
-    return SliverGridRegularTileLayout(
+    return layoutCache = SliverGridRegularTileLayout(
       crossAxisCount: crossAxisCount,
       mainAxisStride: childMainAxisExtent + mainAxisSpacing,
       crossAxisStride: childCrossAxisExtent + crossAxisSpacing,
@@ -107,10 +111,13 @@ class SliverGridDelegateWithExtentAndRatio extends SliverGridDelegate {
 
   @override
   bool shouldRelayout(SliverGridDelegateWithExtentAndRatio oldDelegate) {
-    return oldDelegate.maxCrossAxisExtent != maxCrossAxisExtent ||
+    final flag =
+        oldDelegate.maxCrossAxisExtent != maxCrossAxisExtent ||
         oldDelegate.mainAxisSpacing != mainAxisSpacing ||
         oldDelegate.crossAxisSpacing != crossAxisSpacing ||
         oldDelegate.childAspectRatio != childAspectRatio ||
         oldDelegate.mainAxisExtent != mainAxisExtent;
+    if (flag) layoutCache = null;
+    return flag;
   }
 }