message: Added render function (components need one)
diff: @@ -32,6 +32,9 @@ class NavigationBackAndroid extends React.Component<any, any> {
  componentWillUnmount() {
  BackAndroid.removeEventListener('hardwareBackPress', this.onBack);
  }
  + render() {
  + return null;
  + }
  }
  export default NavigationBackAndroid;
  