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

addBackButtonToRed.js

# App.js

...
class RedScreen extends Component {
  render() {
    return(
      <View style={styles.red}>
        <Text style={styles.text}>This is the Red Screen</Text>
        <TouchableHighlight
          style={styles.button}
          onPress={() => this.props.navigation.goBack()}
        >
          <Text style={styles.text}>Back to Green</Text>
        </TouchableHighlight>
      </View>
    );
  }
}
...