feature: add isFixedHeight parameter support for the JumpTo method of GridView

example/lib/features/gridview/gridview_custom_demo/gridview_custom_demo_page.dart

@@ -3,9 +3,9 @@
  * @Repo: https://github.com/LinXunFeng/flutter_scrollview_observer
  * @Date: 2023-05-21 11:14:46
  */
-import 'package:flutter/material.dart';
 // ignore: implementation_imports
 import 'package:extended_list/src/rendering/sliver_grid.dart';
+import 'package:flutter/material.dart';
 import 'package:loading_more_list/loading_more_list.dart';
 import 'package:scrollview_observer/scrollview_observer.dart';
 

example/lib/features/gridview/gridview_fixed_height_demo/gridView_fixed_height_demo_page.dart

@@ -0,0 +1,110 @@
+/*
+ * @Author: LinXunFeng linxunfeng@yeah.net
+ * @Repo: https://github.com/LinXunFeng/flutter_scrollview_observer
+ * @Date: 2022-08-08 00:20:03
+ */
+import 'package:flutter/material.dart';
+import 'package:scrollview_observer/scrollview_observer.dart';
+import 'package:scrollview_observer_example/typedefs.dart';
+
+class GridViewFixedHeightDemoPage extends StatefulWidget {
+  const GridViewFixedHeightDemoPage({Key? key}) : super(key: key);
+
+  @override
+  State<GridViewFixedHeightDemoPage> createState() =>
+      _GridViewFixedHeightDemoPageState();
+}
+
+class _GridViewFixedHeightDemoPageState
+    extends State<GridViewFixedHeightDemoPage> {
+  static const double _leadingPadding = 1000;
+  static const double _trailingPadding = 100;
+  static const EdgeInsets _padding = EdgeInsets.only(
+    top: _leadingPadding,
+    bottom: _trailingPadding,
+    left: 30,
+    right: 30,
+  );
+
+  List<int> _hitIndexs = [0, 1];
+
+  ScrollController scrollController =
+      ScrollController(initialScrollOffset: _leadingPadding);
+
+  late GridObserverController observerController;
+
+  @override
+  void initState() {
+    super.initState();
+
+    observerController = GridObserverController(controller: scrollController);
+
+    // Trigger an observation manually
+    ambiguate(WidgetsBinding.instance)?.endOfFrame.then(
+      (_) {
+        if (mounted) {
+          // After layout
+          observerController.dispatchOnceObserve();
+        }
+      },
+    );
+  }
+
+  @override
+  void dispose() {
+    observerController.controller?.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text("GridView")),
+      body: GridViewObserver(
+        controller: observerController,
+        onObserve: (result) {
+          final model = result;
+          setState(() {
+            _hitIndexs = model.firstGroupChildList.map((e) => e.index).toList();
+          });
+
+          debugPrint(
+              'firstGroupChildList -- ${model.firstGroupChildList.map((e) => e.index)}');
+          debugPrint('displaying -- ${model.displayingChildIndexList}');
+        },
+        child: _buildGridView(),
+      ),
+      floatingActionButton: FloatingActionButton(
+        child: const Icon(Icons.airline_stops_outlined),
+        onPressed: () {
+          observerController.jumpTo(
+            index: 21,
+            padding: _padding,
+            isFixedHeight: true,
+          );
+        },
+      ),
+    );
+  }
+
+  Widget _buildGridView() {
+    return GridView.builder(
+      padding: _padding,
+      controller: scrollController,
+      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
+        crossAxisCount: 2,
+        crossAxisSpacing: 2,
+        mainAxisSpacing: 5,
+      ),
+      itemBuilder: (context, index) {
+        return Container(
+          color: (_hitIndexs.contains(index)) ? Colors.red : Colors.blue[100],
+          child: Center(
+            child: Text('index -- $index'),
+          ),
+        );
+      },
+      itemCount: 50,
+    );
+  }
+}

example/lib/features/home/home_page.dart

@@ -10,6 +10,7 @@ import 'package:scrollview_observer_example/features/custom_scrollview/sliver_ap
 import 'package:scrollview_observer_example/features/gridview/gridview_ctx_demo/gridview_ctx_demo_page.dart';
 import 'package:scrollview_observer_example/features/gridview/gridview_custom_demo/gridview_custom_demo_page.dart';
 import 'package:scrollview_observer_example/features/gridview/gridview_demo/gridview_demo_page.dart';
+import 'package:scrollview_observer_example/features/gridview/gridview_fixed_height_demo/gridView_fixed_height_demo_page.dart';
 import 'package:scrollview_observer_example/features/gridview/horizontal_gridview_demo/horizontal_gridview_demo_page.dart';
 import 'package:scrollview_observer_example/features/gridview/sliver_grid_demo/sliver_grid_demo_page.dart';
 import 'package:scrollview_observer_example/features/listview/horizontal_listview_demo/horizontal_listview_page.dart';
@@ -29,6 +30,7 @@ import 'package:scrollview_observer_example/features/scene/video_auto_play_list/
 import 'package:scrollview_observer_example/features/scene/visibility_demo/page/visibility_listview_page.dart';
 import 'package:scrollview_observer_example/features/scene/visibility_demo/page/visibility_scrollview_page.dart';
 import 'package:scrollview_observer_example/features/scene/waterfall_flow_demo/waterfall_flow_page.dart';
+import 'package:scrollview_observer_example/features/scene/waterfall_flow_fixed_height_demo/waterfall_flow_fixed_height_page.dart';
 import 'package:tuple/tuple.dart';
 
 typedef PageBuilder = Widget Function();
@@ -123,6 +125,12 @@ class HomePage extends StatelessWidget {
           return const GridViewCtxDemoPage();
         },
       ),
+      Tuple2<String, PageBuilder>(
+        "GridView - Fixed Height",
+        () {
+          return const GridViewFixedHeightDemoPage();
+        },
+      ),
       Tuple2<String, PageBuilder>(
         "GridView - Horizontal",
         () {
@@ -201,6 +209,12 @@ class HomePage extends StatelessWidget {
           return const WaterfallFlowPage();
         },
       ),
+      Tuple2<String, PageBuilder>(
+        "Waterfall Flow - Fixed Height",
+        () {
+          return const WaterfallFlowFixedHeightPage();
+        },
+      ),
       Tuple2<String, PageBuilder>(
         "ScrollView Form",
         () {

example/lib/features/listview/listview_custom_demo/listview_custom_demo_page.dart

@@ -3,9 +3,9 @@
  * @Repo: https://github.com/LinXunFeng/flutter_scrollview_observer
  * @Date: 2023-05-21 10:31:44
  */
-import 'package:flutter/material.dart';
 // ignore: implementation_imports
 import 'package:extended_list/src/rendering/sliver_list.dart';
+import 'package:flutter/material.dart';
 import 'package:loading_more_list/loading_more_list.dart';
 import 'package:scrollview_observer/scrollview_observer.dart';
 

example/lib/features/scene/waterfall_flow_fixed_height_demo/waterfall_flow_fixed_height_page.dart

@@ -0,0 +1,126 @@
+import 'package:flutter/material.dart';
+import 'package:scrollview_observer/scrollview_observer.dart';
+import 'package:waterfall_flow/waterfall_flow.dart';
+
+class WaterfallFlowFixedHeightPage extends StatefulWidget {
+  const WaterfallFlowFixedHeightPage({Key? key}) : super(key: key);
+
+  @override
+  State<WaterfallFlowFixedHeightPage> createState() =>
+      WaterfallFlowFixedHeightPageState();
+}
+
+class WaterfallFlowFixedHeightPageState
+    extends State<WaterfallFlowFixedHeightPage> {
+  BuildContext? grid1Context;
+
+  BuildContext? firstChildCtxInViewport;
+
+  ScrollController scrollController = ScrollController(initialScrollOffset: 0);
+
+  late SliverObserverController observerController;
+
+  @override
+  void initState() {
+    super.initState();
+
+    observerController = SliverObserverController(controller: scrollController);
+  }
+
+  @override
+  void dispose() {
+    observerController.controller?.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Waterfall Flow')),
+      body: SliverViewObserver(
+        child: _buildBody(),
+        controller: observerController,
+        autoTriggerObserveTypes: const [
+          ObserverAutoTriggerObserveType.scrollEnd,
+        ],
+        triggerOnObserveType: ObserverTriggerOnObserveType.directly,
+        // extendedHandleObserve: (context) {
+        //   // An extension of the original observation logic.
+        //   final _obj = ObserverUtils.findRenderObject(context);
+        //   if (_obj is RenderSliverWaterfallFlow) {
+        //     return ObserverCore.handleGridObserve(
+        //       context: context,
+        //       fetchLeadingOffset: () => observeOffset,
+        //     );
+        //   }
+        //   return null;
+        // },
+        sliverContexts: () {
+          return [
+            if (grid1Context != null) grid1Context!,
+          ];
+        },
+        onObserveViewport: (result) {
+          firstChildCtxInViewport = result.firstChild.sliverContext;
+          debugPrint(
+              'current first sliver in viewport - $firstChildCtxInViewport');
+        },
+        onObserveAll: (resultMap) {
+          final result = resultMap[firstChildCtxInViewport];
+          debugPrint('all Observe for current first sliver - $result');
+        },
+      ),
+      floatingActionButton: FloatingActionButton(
+        child: const Icon(Icons.airline_stops_outlined),
+        onPressed: () {
+          observerController.jumpTo(
+            index: 13,
+            isFixedHeight: true,
+            renderSliverType: ObserverRenderSliverType.grid,
+          );
+        },
+      ),
+    );
+  }
+
+  Widget _buildBody() {
+    return CustomScrollView(
+      controller: scrollController,
+      slivers: [
+        _buildGridView(childCount: 50),
+      ],
+    );
+  }
+
+  Widget _buildGridView({
+    required int childCount,
+  }) {
+    return SliverWaterfallFlow(
+      gridDelegate: const SliverWaterfallFlowDelegateWithFixedCrossAxisCount(
+        crossAxisCount: 3,
+        mainAxisSpacing: 15,
+        crossAxisSpacing: 10,
+      ),
+      delegate: SliverChildBuilderDelegate(
+        (BuildContext context, int index) {
+          if (grid1Context != context) grid1Context = context;
+          return Container(
+              height: 50,
+              color: Colors.primaries[index % Colors.primaries.length],
+              alignment: Alignment.topLeft,
+              child: Text(
+                'item: $index',
+                style: const TextStyle(fontSize: 20, color: Colors.white),
+              ));
+        },
+        childCount: childCount,
+      ),
+    );
+  }
+
+  Widget _buildSeparator(double size) {
+    return SliverToBoxAdapter(
+      child: Container(height: size),
+    );
+  }
+}