Code snippet from ReactNav application as featured in http://platypus.is/posts/4

addHeaderTitles.js

# App.js

...
class GreenScreen extends Component {
  static navigationOptions = {
    title: 'Green'
  }
  render() {
    return(
      <View style={styles.green}>
        <Text style={styles.text}>This is the Green Screen</Text>
      </View>
    );
  }
}
...