DraggableScrollableSheet with BouncingScrollPhysics, SliverList, and uneven child sizes behaves erratically #169712
Description
Steps to reproduce
- Run following code
- Expand sheet and scroll to bottom
- Fling down expecting sheet to snap to top
- Repeat 2-3 until sheet misbehaves (see video, it either collapses altogether to the minHeight or bounces too much)
Expected results
DraggableScrollableSheet behaves correctly - the same way one achieves applying workarounds (1) or (3) commend in the code below
Actual results
DraggableScrollableSheet behaves incorrectly:
- either bounces too much (compare to the 2nd video)
- or collapses altogether, missing 0.5 height snap
Code sample
Code sample
import 'package:flutter/material.dart';
void main() => runApp(const App());
class App extends StatelessWidget {
const App({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(home: Material(child: TestPage()));
}
}
class TestPage extends StatelessWidget {
const TestPage({super.key});
@override
Widget build(BuildContext context) {
final children = List<Widget>.generate(12, (_) {
return Padding(
padding: EdgeInsets.only(bottom: 10),
child: Container(color: Colors.green, height: 100),
);
});
// 1st workaround: removing this line 'fixes' the issue
children.insert(0, Container(color: Colors.green, height: 100));
return DraggableScrollableSheet(
shouldCloseOnMinExtent: false,
snap: true,
snapAnimationDuration: const Duration(milliseconds: 220),
snapSizes: [0.5],
maxChildSize: 1,
initialChildSize: 0.5,
minChildSize: 0.2,
builder: (context, scrollController) {
return CustomScrollView(
// 2nd workaround: removing BouncingScrollPhysics 'fixes' the issue
physics: const BouncingScrollPhysics(),
controller: scrollController,
slivers: [
SliverList(
delegate: SliverChildBuilderDelegate((context, index) {
return children[index];
}, childCount: children.length),
),
// 3rd workaround: replacing SliverList with this 'fixes' the issue
// SliverToBoxAdapter(
// child: Column(children: children),
// ),
],
);
},
);
}
}Screenshots or Video
Screenshots / Video demonstration
draggable_scrollable_sheet_issue.mp4
draggable_scrollable_sheet_workaround.mp4
Logs
No response
Flutter Doctor output
Doctor output
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