Ahmed El-Helw
3998650468
Summary: Add a README file explaining the purpose of Nodes and how to enable it within an app. Reviewed By: JoelMarcey, lacker Differential Revision: D4349517 fbshipit-source-id: ec26ebb37039e7c23ecd2cf4b482fa21ca8beeda
1.9 KiB
Nodes
Nodes is an experimental, alternate version of
UIImplementation for ReactNative on Android. It has two main advantages over the existing UIImplementation:
- Support for
overflow:visibleon Android. - More efficient generation of view hierarchies.
The intention is to ultimately replace the existing UIImplementation on
Android with Nodes (after all the issues are ironed out).
How to test
In a subclass of ReactNativeHost, add this:
@Override
protected UIImplementationProvider getUIImplementationProvider() {
return new FlatUIImplementationProvider();
}
How it Works
The existing
UIImplementation maps all non-layout tags to Views (resulting in an almost 1:1 mapping of tags
to Views, with the exception of some optimizations for layout only tags that
don't draw content). Nodes, on the other hand, maps react tags to a set of
DrawCommands. In other words, an <image> tag will often be mapped to a
Drawable instead of an ImageView and a <text> tag will be mapped to a
Layout instead of a TextView. This helps flatten the resulting View
hierarchy.
There are situations where DrawCommands are promoted to Views:
- Existing Android components that are wrapped by React Native (for example,
ViewPager,ScrollView, etc). - When using a
Viewis more optimal (for example,opacity, to avoid unnecessary invalidations). - To facilitate the implementation of certain features (accessibility, transforms, etc).
This means that existing custom ViewManagers should continue to work as they
did with the existing UIImplementation.
Limitations and Known Issues
LayoutAnimations are not yet supportedzIndexis not yet supported