Summary:
This avoids reordering views because it created some bugs when the native hierarchy is different from the shadow views. This leverages `layer.zPosition` and takes z-index in consideration when we check what view should be the target of a touch.
**Test plan**
Tested that this fixes some layout issues that occurred when using sticky headers in the Expo home screen.
Closes https://github.com/facebook/react-native/pull/14011
Differential Revision: D5108437
Pulled By: shergin
fbshipit-source-id: 0abfe85666e9d236a190e6f54cdd5453cacfbcac
Summary: Reveting the recent view clipping changes, since it doesn't work well with modals and the fix is not super simple.
Reviewed By: mmmulani
Differential Revision: D4204490
fbshipit-source-id: 510f2b04c604b3f3a223dc4accb424b030876fbe
Summary:
This diff implement the CSS z-index for React Native iOS views. We've had numerous pull request for this feature, but they've all attempted to use the `layer.zPosition` property, which is problematic for two reasons:
1. zPosition only affects rendering order, not event processing order. Views with a higher zPosition will appear in front of others in the hierarchy, but won't be the first to receive touch events, and may be blocked by views that are visually behind them.
2. when using a perspective transform matrix, views with a nonzero zPosition will be rendered in a different position due to parallax, which probably isn't desirable.
See https://github.com/facebook/react-native/pull/7825 for further discussion of this problem.
So instead of using `layer.zPosition`, I've implemented this by actually adjusting the order of the subviews within their parent based on the zIndex. This can't be done on the JS side because it would affect layout, which is order-dependent, so I'm doing it inside the view itself.
It works as follows:
1. The `reactSubviews` array is set, whose order matches the order of the JS components and shadowView components, as specified by the UIManager.
2. `didUpdateReactSubviews` is called, which in turn calls `sortedSubviews` (which lazily generates a sorted array of `reactSubviews` by zIndex) and inserts the result into the view.
3. If a subview is added or removed, or the zIndex of any subview is changed, the previous `sortedSubviews` array is cleared and `didUpdateReactSubviews` is called again.
To demonstrate it working, I've modified the UIExplorer example from https://github.com/facebook/react-native/pull/7825
Reviewed By: javache
Differential Revision: D3365717
fbshipit-source-id: b34aa8bfad577bce023f8af5414f9b974aafd8aa
Summary:
This diff removes calls to `-updateClippedSubviews` by only re-clipping when the scroll view moves by a certain number of pixels.
leeway = 50pt => 46.9% of calls removed
leeway = 10pt => 13.2% " " "
Janic Duplessis
Martin Kralik
Nick Lockwood
Alex Akers