Summary: Adds the API that enables the navigation events capturing and bubbling which is the feature
that is enabled if the nested navigation contexts is created by the navigator.
This would allow developer to observe or reconcile navigation events within the navigation tree.
public
./Libraries/FBReactKit/jest
Reviewed By: zjj010104
Differential Revision: D2546451
fb-gh-sync-id: dfc9d16defaa563b9e80fd751a20570f6e524b74
Summary: @public
Add method `stopPropagation` and `stop` to NavigationEvent so we can stop event easily once event bubbling and capturing is supported.
Reviewed By: @fkgozali
Differential Revision: D2471903
Summary:
While adeveloper requests the emitter to emit an event, the emitter
may not emit the event immediately instead of putting the request
into a queue and process it later.
This diff allows the developer to provide a callback which will be called
when the event has been emitted.
For instance:
```
class NavigationContext {
push(nextRoute) {
var nextStack = this._stack.push(nextRoute);
this.emit(
'change',
{
reason: 'push',
nextStack: nextStack,
nextRoute: nextRoute,
},
this._onPush
);
}
_onPush(event){
if (event.defaultPrevented) {
return;
}
this._stack = event.nextStack;
this.emit('change');
}
}
```
of the navigator component.
Summary:
Per offline discussion with @evv, we'd like to deprecate the `onDidFocus` and `onWillFocus`
API that makes it really hard for the descendent children of a navigator to observe its focus
change events.
@public
Since for now the descendent children do have access to the navigator via `this.props.navigator`,
this diff makes it easy to observe the focus change event by doing:
```
this.props.navigator.addListener('willfocus', this._onFocus);
```
The goal is to make the event system in navigator more useful and maintainable.
Test Plan:
Test Video: https://www.facebook.com/pxlcld/mrzS
1. jest: ./Libraries/FBReactKit/js/runTests.js NavigationEventEmitter
2. Load UI Explorer: <Navigator />, see console logs that shows the focus change events fires.
Hedger Wang
Martin Konicek