Facilitating re-render, state-update, etc on navigation change

react-native-router-flux doesn't currently make it possible to hook onto the action on a Scene navigation event, which makes it impossible update a Scene purely based on navigation. Instead a Scene is currently only rendered if the props provided to the scene are changed, which is not always possible or convenient. This module implements a reducer for the navigation state in which it is possible to indicate which scene components would like to have a method (navigationStateRouter) called when a Scene is change/update according to a Scene navigation constant.

Installation

npm install --save react-native-router-flux-hooks

+import NavigationStateHandler from 'react-native-router-flux-focus-hook'
+const navigationStateHandler = new NavigationStateHandler()

class App extends Component {
  render() {
    return (
      <Router 
+      createReducer={navigationStateHandler.getReducer.bind(navigationStateHandler)} 
+      navigationStateHandler={navigationStateHandler}
        >
        <Scene key="root" component={MainComponent}>
        <Scene key="root" component={DynamicComponent}>
        <Scene key="root" component={OtherComponent}>
      </Router>
  }
}

This ensures that we can hook on to when navigation actions are fired and that navigationStateRouter is available to every scene component.

Next indicate that a scene component wants to have its handleNavigationSceneFocus method called when the scene is focused: handleNavigationSceneRefresh method called when the scene is refreshed: handleNavigationScene${ActionConst['event']} method called when the scene is (ActionConst['event']):

NavigationStateHandler comes equipped with hooks for ActionConst.FOCUS and ActionConst.REFRESH.
To handle other events, simply add that event like so: 
+const navigationStateHandler = new NavigationStateHandler();
navigationStateRouter.addEvent(ActionConst.RESET);

then you can use this.props.navigationStateHandler.registerRESETHook in your component..

note: hook name is always "register${ActionConst['eventName']}Hook" and
handler "handleNavigationSceneF${ActionConst['eventName']}"

class DynamicComponent extends Component {
  componentDidMount() {
    const registerHandler = `register${ActionConst['event']}Hook`; 
+   this.props.navigationStateHandler.registerFOCUSHook(this);
+   this.props.navigationStateHandler[registerHandler](this);
  }

  componentWillUnmount() {
    const unregisterHandler = `register${ActionConst['event']}Hook`; 
+   this.props.navigationStateHandler.unregisterFOCUSHook(this)
+   this.props.navigationStateHandler[unregisterHandler](this);
  }

  handleNavigationSceneFOCUS() {
+   this.setState({ date: "load new data" })
  }
}

And finally implement in your appropriate handleNavigationScene handler the functionality you need :)

Pull-requests welcome!