[Android] Fix CollectionView LinearItemsLayout first/last items clipped when ItemSpacing changes at runtime#34664
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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!
Issue Details
CollectionView with LinearItemsLayout, the first and last items become truncated/clipped after changing the ItemSpacing value at runtime. This affects both vertical and horizontal list orientations on Android.
Note: This is inflight/candate branch changes where exsiting PR #27093 causes the regression on this branch. So added this new fix to overcome the regression.
Root Cause
PR #27093 changed SpacingItemDecoration.GetItemOffsets to zero out the outer edge offsets (outRect.Top = 0 for item 0, outRect.Bottom = 0 for last item) for all layout types including LinearItemsLayout. However, MauiRecyclerView.UpdateItemSpacing still applied negative padding (SetPadding(-offset, ...)) on the RecyclerView for linear layouts. This conflict caused the first and last items to be pulled outside the visible area and clipped, since the positive offset that was supposed to cancel the negative padding was removed.
Description of Change
Added a _removeOuterEdgeSpacing boolean flag to SpacingItemDecoration, set to true only for GridItemsLayout. In GetItemOffsets, an early return is added when _removeOuterEdgeSpacing is false, skipping the edge-zeroing logic for LinearItemsLayout. This restores the correct balanced behavior for linear lists: the positive outRect offset (+N) and the negative RecyclerView padding (-N) cancel each other out at the edges, keeping the first and last items correctly positioned at the screen boundary.
Validated the behavior in the following platforms
Issues Fixed
Fixes #34636
Output ScreenShot