cd0082f04f
<!-- Thanks for filing a pull request! Reviewers are typically assigned within a week of filing a request. To learn more about code review, see our documentation on Tree Hygiene: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md --> fixes #140701 This PR fixes an issue where a DraggableScrollableSheet with `snap` set to true and `shouldCloseOnMinExtent` set to true may not close when dragged downward. The issue was caused by round-off errors accumulated by `addPixelDelta` method, which could lead to `extent.currentSize` not matching the `extent.minSize` exactly when the bottom is reached. I added logic to correct it when the snapping ballistic animation is complete. <details> <summary>Sample code</summary> ```Dart import 'package:flutter/material.dart'; void main() { runApp(MyApp()); } class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return MaterialApp( home: HomePage(), ); } } class HomePage extends StatelessWidget { const HomePage({super.key}); @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("DraggableScrollableSheet Test"), ), body: Center( child: ElevatedButton( child: Text("Open"), onPressed: () { showModalBottomSheet( context: context, showDragHandle: true, isScrollControlled: true, builder: (context) => _buildBottomSheet(), ); }, ), ), ); } Widget _buildBottomSheet() { return NotificationListener<DraggableScrollableNotification>( onNotification: (notification) { print(notification.extent); return false; }, child: DraggableScrollableSheet( expand: false, snap: true, shouldCloseOnMinExtent: true, maxChildSize: 0.9, minChildSize: 0.25, builder: (context, scrollController) { return ListView.builder( controller: scrollController, itemCount: 100, itemBuilder: (context, index) { return ListTile( title: Text("Item $index"), ); }, ); }, ), ); } } ``` </details> | Before applying fix | After | | --- | --- | | * Occurs with probability <video src="https://github.com/user-attachments/assets/ffd2d097-3ed5-4775-90d5-950092d49591"> | <video src="https://github.com/user-attachments/assets/0f20cb81-3444-40a3-a84d-ed4bff15887e"> | ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
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