Navigator with buttons injected from pages

//In the page "Home", I want to have the right nav button to show
//a settings modal that resides in "Home" component.

componentWillMount() {
  this.props.route.navbarTitle = "Home";

  this.props.route.rightNavButton = {
    text: "Settings",
    onPress: this._ShowSettingsModal.bind(this)
  };
}

'use strict';

import React, {Component} from 'react';
import ReactNative from 'react-native';

const {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  Navigator,
  Alert,
  TouchableHighlight
} = ReactNative;


//This is the app container that contains the navigator stuff
class AppContainer extends Component {

    renderScene(route, navigator) {
        switch(route.name) {
            case "Home":
      //You must pass route as a prop for this trick to work properly
            return <Home route={route} navigator={navigator} {...route.passProps}  />
            default:
            return (
        <Text route={route}
        style={styles.container}>
            Your route name is probably incorrect {JSON.stringify(route)}
            </Text>
      );
        }
    }
  
  render() {
    return (
      <Navigator
        navigationBar={
          <Navigator.NavigationBar
            style={ styles.navbar }
            routeMapper={ NavigationBarRouteMapper } />
        }
  
        initialRoute={{ name: 'Home' }}
        renderScene={ this.renderScene }
        
      />
    );
  }
}


//Nothing fancy here, except for checking for injected buttons.
//Notice how we are checking if there are injected buttons inside the route object.
//Also, we are showing a "Back" button when the page is not at index-0 (e.g. not home)
var NavigationBarRouteMapper = {
  LeftButton(route, navigator, index, navState) {
    if(route.leftNavButton) {
      return (
        <TouchableHighlight
        style={styles.leftNavButton}
        underlayColor="transparent"
        onPress={route.leftNavButton.onPress}>
          <Text style={styles.navbarButtonText}>{route.leftNavButton.text}</Text>
        </TouchableHighlight>
      );
    }
    else if(route.enableBackButton) {
      return (
        <TouchableHighlight
        style={styles.leftNavButton}
        underlayColor="transparent"
        onPress={() => navigator.pop() }>
          <Text style={styles.navbarButtonText}>Back</Text>
        </TouchableHighlight>
      );
    }
  },
  RightButton(route, navigator, index, navState) {
    if(route.rightNavButton) {
      return (
        <TouchableHighlight
        style={styles.rightNavButton}
        underlayColor="transparent"
        onPress={route.rightNavButton.onPress}>
          <Text style={styles.navbarButtonText}>{route.rightNavButton.text}</Text>
        </TouchableHighlight>
      );
    }
  },
  Title(route, navigator, index, navState) {
    //You can inject the title aswell.  If you don't we'll use the route name.
    return (<Text style={styles.navbarTitle}>{route.navbarTitle || route.name}</Text>);
  }
};
            
//This is considered a sub-page that navigator is showing
class Home extends Component {
  
  //This trick depends on that componentWillMount fires before the navbar is created
  componentWillMount() {
        this.props.route.navbarTitle = "Home";
    
        this.props.route.rightNavButton = {
            text: "Button",
            onPress: this._doSomething.bind(this)
        };
    }
  
  //This method will be invoked by pressing the injected button.
  _doSomething() {
      Alert.alert(
      'Awesome, eh?',
      null,
      [
        {text: 'Indeed'},
      ]
    )
  }
  
  render() {
    return (
      <View style={styles.container}>
            <Text>You are home</Text>
        </View>
    );
  }
}

var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
    marginTop: 66
  },
  navbar: {
    backgroundColor: '#ffffff',
  },
  navbarTitle: {
    marginVertical: 10,
    fontSize: 17
  },
  leftNavButton: {
    marginVertical: 10,
    paddingLeft: 8,
 },
  rightNavButton: {
    marginVertical: 10,
    paddingRight: 8,
  },
  navbarButtonText: {
    fontSize: 17,
    color: "#007AFF"
  }
});

AppRegistry.registerComponent('AppContainer', () => AppContainer);