Fix inverted FlatList RefreshControl indicator position

[Navjot1806]

Summary

Fixes #17553

When using an inverted FlatList with onRefresh/refreshing, the RefreshControl activity indicator appears at the visual bottom of the list instead of the visual top. This is because the scaleY: -1 transform applied to the ScrollView flips the entire view including the RefreshControl.

This PR automatically sets progressViewOffset on the RefreshControl when the list is inverted, repositioning the refresh indicator at the visual top of the list. The offset is calculated from the visible height of the scroll view after layout.

Changes

• VirtualizedList.js: In _defaultRenderScrollComponent, when isInvertedVirtualizedList is true and the user hasn't provided a custom progressViewOffset, automatically calculate and pass progressViewOffset equal to visibleLength to reposition the refresh indicator at the visual top.
• VirtualizedList-test.js: Added 3 new test cases:
  • Verifies progressViewOffset is set on RefreshControl when inverted and layout is known
  • Verifies progressViewOffset is NOT set when the list is not inverted
  • Verifies user-provided progressViewOffset is respected when inverted

Behavior

Scenario	Before	After
Inverted + onRefresh	Indicator at visual bottom	Indicator at visual top
Non-inverted + onRefresh	Indicator at top (unchanged)	Indicator at top (unchanged)
Inverted + custom progressViewOffset	Uses custom value	Uses custom value (unchanged)

Note

This fix repositions the visual indicator to the correct location. The pull-to-refresh gesture direction (which is tied to the native scroll view behavior) would require native-level changes to fully resolve and is tracked separately.

Changelog

[GENERAL] [FIXED] - Fix inverted FlatList RefreshControl indicator appearing at the visual bottom instead of visual top (#17553)

Test Plan

• Added 3 new unit tests in VirtualizedList-test.js that verify the progressViewOffset behavior for inverted lists
• All existing 76 tests continue to pass
• All FlatList and VirtualizedSectionList tests pass

🤖 Generated with Claude Code

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