[iOS] RTL column mirroring in UICollectionView - fix #32372
Conversation
Explicitly sets the semantic content attribute on the native UICollectionView to ensure compositional layouts mirror columns correctly in right-to-left (RTL) scenarios. This addresses an issue where the platform view's semantic attribute does not propagate to native children not backed by IView.
|
Hey there @@kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed. |
There was a problem hiding this comment.
Pull Request Overview
This PR fixes an issue where iOS UICollectionView compositional layouts don't properly mirror columns in right-to-left (RTL) flow directions. The fix explicitly sets the SemanticContentAttribute on the native UICollectionView to ensure RTL layout behavior is correctly applied.
- Adds explicit semantic content attribute handling for the UICollectionView based on FlowDirection
- Maps FlowDirection enum values to appropriate UISemanticContentAttribute values
- Only updates the SemanticContentAttribute when it differs from the desired value
| case FlowDirection.MatchParent: | ||
| // Let it inherit from the parent view we just updated | ||
| desiredAttr = UISemanticContentAttribute.Unspecified; | ||
| break; |
There was a problem hiding this comment.
The switch statement can be simplified by initializing desiredAttr within the switch expression or handling the MatchParent case implicitly. Since desiredAttr is already initialized to Unspecified (line 319), the MatchParent case at line 328-331 is redundant and can be removed. Alternatively, use a switch expression to make the intent clearer.
| case FlowDirection.MatchParent: | |
| // Let it inherit from the parent view we just updated | |
| desiredAttr = UISemanticContentAttribute.Unspecified; | |
| break; |
|
/azp run |
|
Azure Pipelines successfully started running 3 pipeline(s). |
| } | ||
|
|
||
| if (CollectionView.SemanticContentAttribute != desiredAttr) | ||
| { |
There was a problem hiding this comment.
Compositional and flow layouts may not re-query attributes immediately, requires to force a layout pass?
Ahamed-Ali
added
area-controls-collectionview
3 participants
Note
Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!
Description of Change
Explicitly sets the semantic content attribute on the native UICollectionView to ensure compositional layouts mirror columns correctly in right-to-left (RTL) scenarios. This addresses an issue where the platform view's semantic attribute does not propagate to native children not backed by IView.
Screen.Recording.2025-11-04.at.00.40.34.mov
Screen.Recording.2025-11-04.at.00.37.54.mov
Issues Fixed
Fixes #32359