如何检测用户何时退出我的应用程序？

Question

I'm writing an android app and I want to remove the user from an array when he exit the app. I tried using the onStop() method, but it's not woking as I desire, because whenever an activity changes, the user is removed from the array.

I need a way to execute a method when the user has removed the app from "recent activities". Any suggestions on the matter?

Answer 1

You can track the back key so when the user presses it to exit the app you do what you want.

 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
       if ((keyCode == KeyEvent.KEYCODE_BACK)) {
        //YOUR CODE HERE
    finish(); //<<<------MUST BE USED SO THAT THE BUTTON WILL ACTUALLY FINISH THE APP
        }
  return super.onKeyDown(keyCode, event);
   }

Otherwise you can try the onPause() method instead of the onStop. Android doesnt recommend using the onStop to save data etc. I think though that the back key is best

Answer 2

I need a way to execute a method when the user has removed the app from "recent activities"

When you swipe an app from the list, it actually just stops all the app's services (and not the app itself!). You may want to consider creating a service just for this purpose so that when the service is killed, you are notified via onTaskRemoved .

You can read some more here