UPDATE 04/2018 :

Things have change since my first answer, and today two massive libraries are relevant for navigation : react-navigation and react-native-navigation.

I will wrote an example for react-navigation which is an easy to use library and full JS maintain by serious people from the community.

First install the library :

yarn add react-navigation

or

npm install --save react-navigation

Then in your app entry point (index.js) :

import Config from './config';



import { AppRegistry } from 'react-native';

import { StackNavigator } from 'react-navigation';



export const AppNavigator = StackNavigator(Config.navigation);

AppRegistry.registerComponent('appName', () => AppNavigator);

You can see that we pass an object to the StackNavigator, it's all ours screens configuration, here is an example of configuration :

import HomeScreen from ./HomeScreen;

import SettingsScreen from ./SettingsScreen;



const Config = {

      navigation: {

          Home: {

            screen: HomeScreen

          },

          Settings: {

            screen: SettingsScreen,

          }

       }

    }

Now the app know each screen we got. We can simply tell the navigate function to go to our Setting Screen.
Let's watch our Home Screen :

class HomeScene extends Component {



      constructor(props) {

          super(props);

      }



      render () {

        return (

        <View>

            <Button

              title=Go to Settings

              onPress={() => this.props.navigation.navigate('Settings')}

            />

        </View>



        );

      }

    }

As you can see, the navigation will hydrate the props. And from here you can make what you want.

Go to the library documentation to see all you can do : change the header type, the title, navigation type, ...

PREVIOUS ANSWER :

Watch this example:
https://github.com/h87kg/NavigatorDemo

It's useful and a well written Navigator example, better than the one above you just wrote, I think.

Mainly watch the relationship between LoginPage.js and MainPage.js