Fix iOS Paper Scroll Event RTL check (#40751)

NickGerleman · facebook-github-bot · commit c40fc313ca9d · 2023-10-10T11:43:14.000-07:00
Summary: Pull Request resolved: #40751 In D48379915 I fixed inverted `contentOffset` in `onScroll` events on iOS. I thought I tested on Paper, but I think this was during a period where the Paper route in Catalyst was actually launching Fabric (oops). In Paper, at least under `forceRTL` and English, `[UIApplication sharedApplication].userInterfaceLayoutDirection` is not set to RTL. We instead have a per-view `reactLayoutDirection` we should be reading. This sort of thing isn't currently set on Fabric, which checks application-level RTL. This seems... not right with being able to set `direction` in a subtree context, but Android does the same thing, and that would take some greater changes. Changelog: [iOS][Fixed] - Fix iOS Paper Scroll Event RTL check Reviewed By: luluwu2032 Differential Revision: D50098310 fbshipit-source-id: e321fca7b2f7983e903e23237bc2d604c72f98a3
diff --git a/packages/react-native/React/Views/ScrollView/RCTScrollView.m b/packages/react-native/React/Views/ScrollView/RCTScrollView.m
@@ -1058,7 +1058,7 @@ - (void)sendScrollEventWithName:(NSString *)eventName
   }
 
   CGPoint offset = scrollView.contentOffset;
-  if ([UIApplication sharedApplication].userInterfaceLayoutDirection == UIUserInterfaceLayoutDirectionRightToLeft) {
+  if ([self reactLayoutDirection] == UIUserInterfaceLayoutDirectionRightToLeft) {
     offset.x = scrollView.contentSize.width - scrollView.frame.size.width - offset.x;
   }
 

Original file line number	Diff line number	Diff line change
`@@ -1058,7 +1058,7 @@ - (void)sendScrollEventWithName:(NSString *)eventName`
`1058`	`1058`	`}`
`1059`	`1059`
`1060`	`1060`	`CGPoint offset = scrollView.contentOffset;`
`1061`		`- if ([UIApplication sharedApplication].userInterfaceLayoutDirection == UIUserInterfaceLayoutDirectionRightToLeft) {`
	`1061`	`+ if ([self reactLayoutDirection] == UIUserInterfaceLayoutDirectionRightToLeft) {`
`1062`	`1062`	`offset.x = scrollView.contentSize.width - scrollView.frame.size.width - offset.x;`
`1063`	`1063`	`}`
`1064`	`1064`