Created
July 14, 2024 23:02
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Find scrollables in viewport
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| import 'package:flutter/material.dart'; | |
| void main() { | |
| runApp(MyApp()); | |
| } | |
| class MyApp extends StatelessWidget { | |
| @override | |
| Widget build(BuildContext context) { | |
| return MaterialApp( | |
| home: Scaffold( | |
| appBar: AppBar( | |
| title: Text('Scrollable Widgets in Viewport'), | |
| ), | |
| body: HomeScreen(), | |
| ), | |
| ); | |
| } | |
| } | |
| class HomeScreen extends StatefulWidget { | |
| @override | |
| _HomeScreenState createState() => _HomeScreenState(); | |
| } | |
| class _HomeScreenState extends State<HomeScreen> { | |
| final GlobalKey _key = GlobalKey(); | |
| List<Widget> scrollableWidgets = []; | |
| @override | |
| void initState() { | |
| super.initState(); | |
| WidgetsBinding.instance.addPostFrameCallback((_) { | |
| findScrollableWidgets(); | |
| }); | |
| } | |
| void findScrollableWidgets() { | |
| final RenderObject? rootRenderObject = | |
| _key.currentContext?.findRenderObject(); | |
| if (rootRenderObject == null) return; | |
| final List<Widget> foundScrollables = []; | |
| void visitChildren(Element element) { | |
| element.visitChildren((child) { | |
| if (child.widget is ScrollView) { | |
| final RenderObject renderObject = child.renderObject!; | |
| if (_isWithinViewport(rootRenderObject as RenderBox, renderObject)) { | |
| foundScrollables.add(child.widget); | |
| } | |
| } | |
| visitChildren(child); | |
| }); | |
| } | |
| visitChildren(_key.currentContext as Element); | |
| setState(() { | |
| scrollableWidgets = foundScrollables; | |
| }); | |
| } | |
| bool _isWithinViewport(RenderBox viewport, RenderObject renderObject) { | |
| final Size viewportSize = viewport.size; | |
| final Offset viewportOffset = viewport.localToGlobal(Offset.zero); | |
| final Rect viewportRect = viewportOffset & viewportSize; | |
| final Size renderObjectSize = renderObject.paintBounds.size; | |
| final Offset renderObjectOffset = | |
| (renderObject as RenderBox).localToGlobal(Offset.zero); | |
| final Rect renderObjectRect = renderObjectOffset & renderObjectSize; | |
| return viewportRect.overlaps(renderObjectRect); | |
| } | |
| @override | |
| Widget build(BuildContext context) { | |
| return Column( | |
| children: [ | |
| Expanded( | |
| child: SingleChildScrollView( | |
| key: _key, | |
| child: Column( | |
| children: [ | |
| ListView.builder( | |
| shrinkWrap: true, | |
| physics: NeverScrollableScrollPhysics(), | |
| itemCount: 20, | |
| itemBuilder: (context, index) { | |
| return ListTile( | |
| title: Text('Item $index'), | |
| ); | |
| }, | |
| ), | |
| GridView.builder( | |
| shrinkWrap: true, | |
| physics: NeverScrollableScrollPhysics(), | |
| gridDelegate: SliverGridDelegateWithFixedCrossAxisCount( | |
| crossAxisCount: 2, | |
| ), | |
| itemCount: 20, | |
| itemBuilder: (context, index) { | |
| return Card( | |
| child: Center(child: Text('Card $index')), | |
| ); | |
| }, | |
| ), | |
| ], | |
| ), | |
| ), | |
| ), | |
| ElevatedButton( | |
| onPressed: () { | |
| findScrollableWidgets(); | |
| print('Found ${scrollableWidgets.length} scrollable widgets'); | |
| for (var widget in scrollableWidgets) { | |
| print(widget.runtimeType); | |
| } | |
| }, | |
| child: Text('Find Scrollable Widgets'), | |
| ), | |
| ], | |
| ); | |
| } | |
| } |
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