In iOS, you can do rctRootView.appProperties = newProps, and it will update the root view with new props. On android it doesn't seem to be implemented.

This behavior is critical for my use case of incrementally adopting react native in a large android app.

I think I want a function like ReactRootView.updateProps(Bundle props) that would look something like

public void updateProps(Bundle newProps) {
  WritableNativeMap appParams = new WritableNativeMap();
  Double rootTag = MagicallyGetTheRootTag() // <- the rootTag isn't actually stored anywhere at the moment
  appParams.putDouble("rootTag", rootTag);
  appParams.putMap("initialProps", newProps);
  final CatalystInstance catalystInstance = mReactInstanceManager.getCurrentReactContext().getCatalystInstance();
  String jsAppModuleName = this.getJSModuleName();
  catalystInstance.getJSModule(AppRegistry.class).runApplication(jsAppModuleName, appParams);
}

based on the startReactApplication fn

Before I made a PR I wanted to check my direction -- does it look reasonable? I think I'll have to store the rootTag on the ReactRootView instance, b/c I can't find anywhere else that it's already stored.