mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
adca933962
Issue: #173019 This pull request adds support for the `semanticIndexOffset` parameter to the `SliverList.builder`, `SliverFixedExtentList.builder`, and `SliverGrid.builder` constructors in Flutter. This allows developers to offset the starting semantic index for items in these slivers, which is important for accessibility scenarios (such as when combining multiple slivers). The changes are thoroughly tested with new widget tests to ensure correct behavior. **Accessibility improvements:** * Added `semanticIndexOffset` parameter to the constructors of `SliverList.builder`, `SliverFixedExtentList.builder`, and `SliverGrid.builder`, and ensured it is passed to the underlying `SliverChildBuilderDelegate`. This allows customization of the starting semantic index for sliver children. [[1]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR219) [[2]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR228) [[3]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR476) [[4]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR485) [[5]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR751) [[6]](diffhunk://#diff-a7ccc8e04affff00abaa0800e680e94c325930dac396f134a70ce5c5c17f8c4dR760) **Testing:** * Added a new test for `SliverList.builder` to verify that the `semanticIndexOffset` is respected in the generated semantics tree. [[1]](diffhunk://#diff-9aec0ee8c35ea1c71be420610fe37f772e45b5c1f715285fe76ac5ba328ea76dR366-R382) [[2]](diffhunk://#diff-9aec0ee8c35ea1c71be420610fe37f772e45b5c1f715285fe76ac5ba328ea76dR446-R474) * Added a new test for `SliverFixedExtentList.builder` to verify correct semantics index offsetting. * Added a new test for `SliverGrid.builder` to ensure it respects the `semanticIndexOffset` parameter. ## 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. - [ ] 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. --------- Co-authored-by: Loïc Sharma <737941+loic-sharma@users.noreply.github.com>