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

react-native-router-flux doesn't currently make it possible to hook onto the action when a Scene is brought into focus, 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 brought into focus.

Installation

npm install --save leifdenby/react-native-router-flux-focus-hook

Where your routes are defined import NavigationStateHandler from react-native-router-flux-focus-hook (sorry about the rather awkward name) and change the navigation state reducer

+import NavigationStateHandler from 'react-native-router-flux-focus-hook'

class App extends Component {
  render() {
+   const navigationStateHandler = new NavigationStateHandler()

    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 focussed:

class DynamicComponent extends Component {
  componentDidMount() {
+   this.props.navigationStateHandler.registerFocusHook(this)
  }

  componentWillUnmount() {
+   this.props.navigationStateHandler.unregisterFocusHook(this)
  }

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

And finally implement in handleNavigationSceneFocus the functionality you need :)

Pull-requests welcome!