React-Native BackHandler始终在Android中关闭App（硬件返回）

Question

I'm building a App with react-native v0.44.0 using redux v5.0.5 and react-navigation v1.0.0-beta.11 . The routing is done with nested navigators, one main StackNavigator and DrawerNavigator.
I'm handling all navigation events in a navigation reducer, also the hardware back press on Android using BackHandler. Now comes the weird part (for me), I've implemented the BackHandler event handlers like so:

import { BackHandler, Modal, View } from 'react-native';
import { NavigationActions } from 'react-navigation';    
import { HARDWARE_BACK_PRESS } from '../helpers/NavTypes';

constructor(props) {
  super(props);
  this.handleBack = this.handleBack.bind(this);
}

componentWillMount() {
  BackHandler.addEventListener(HARDWARE_BACK_PRESS, this.handleBack);
}

componentWillUnmount() {
  BackHandler.removeEventListener(HARDWARE_BACK_PRESS, this.handleBack);
}

handleBack() {
  const navAction = NavigationActions.back();

  this.props.navigation.dispatch(navAction);
  return true;
}

In my navigation reducer I'm handling the Navigation/BACK action type and keep track of my state. Now, when I'm pressing the hardware back button on my Android device or in the emulator, I can see thanks to redux-logger and the React Native debugger that the navigation action is dispatched correctly and the previous shown screen appears, but the app closes anyway. This happens also when I alter the handleBack method to something like this:

handleBack() {
  return true;
}

Every time the hardware back button is pressed, the App still closes. I did some step-debugging in node_modules/react-native/Libraries/Utilities/BackHandler.android.js , inside of RCTDeviceEventEmitter.addListener I can see that my event listeners are registered and invokeDefault is set to true in the loop. addListener is exited but the App still closes. Does anyone know if there is some point there react-navigation and redux are overriding the behaviour of the hardware back button at some top level I'm not aware of?
I've setup a second plain RN project without react-navigation and redux, implementing the same BackHandler event listeners (also returning true) and the app won't close. So, right now this leaves me a bit puzzled.

Answer 1

I'm using react-navigation and I also handle the os back button. It works fine for me. May be you can try this out. Note that handleBack must return true if you are performing any other task than closing the app. If not it will close the app immediately.

 componentWillMount() {
  BackHandler.addEventListener(HARDWARE_BACK_PRESS, () => { return this.handleBack.bind(this)() });
}

Answer 2

I had the same problem, returning true wouldn't update. Running react-native run-android again after the changes fixed the problem for me.