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When rapidly dragging items in a ReorderableList before animations complete, items would jump to their expected positions rather than smoothly transitioning. ## Problem <p align="center"> <img src="https://github.com/user-attachments/assets/0efb250c-2960-4942-959f-59eccc20cefb" alt="demo2" width="250"> </p> The issue occurs when a reorder animation is interrupted by starting a new drag operation. The interrupted animation would reset to the starting position of the original animation rather than capturing the current animated position, causing a visual jump. ## Solution This PR fixes the issue by: 1. Storing the previous target offset before updating to a new target 2. When an animation is interrupted, calculating the actual current position based on the animation's progress 3. Using this calculated position as the new starting point for the next animation <p align="center"> <img src="https://github.com/user-attachments/assets/c24e4834-1c6b-41c1-8f44-17b4c79e0993" alt="demo2" width="250"> </p> This PR is part of a series of `ReorderableList` enhancements I've developed for [TimeFinder](https://timefinder.app): - #172740 - #172380 - #172739 - #172738 Fixes #173243 ## Code Changes ```dart // Before _startOffset = offset; // After final double currentAnimValue = Curves.easeInOut.transform(_offsetAnimation\!.value); final Offset currentPosition = Offset.lerp(_startOffset, previousTarget, currentAnimValue)\!; _startOffset = currentPosition; ``` This ensures smooth transitions without visual jumping, making rapid reordering gestures feel more responsive and natural. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I listed at least one issue that this PR fixes in the description above. - [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 [migration guide] as needed. - [x] All existing and new tests are passing. - [x] The analyzer (`flutter analyze --flutter-repo`) does not report any problems on my PR. - [x] I am willing to follow-up on review comments in a timely manner. [Contributor Guide]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md [Flutter Style Guide]: https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [test-exempt]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#tests [breaking change policy]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#handling-breaking-changes [migration guide]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#create-a-migration-guide
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