How do I manually pause an activity in Android?

Question

When you press the back button in Android it calls finish() under the hood, and I want it to be replaced with a pause behavior, and I have found no documentation that let's you trigger that manually.

EDIT: Ok, this needs more code I guess

public boolean onKeyDown(int keyCode, KeyEvent event)
{
    int Action = event.getAction();
    if (Action == KeyEvent.ACTION_DOWN)
    {
        if (event.getKeyCode() == KeyEvent.KEYCODE_BACK)
        {
         //Default Implementation calls finish();
         //I want to call Pause, which should call onPause and then send my app in the background !

          }
      }
}

I just tried onBackPressed, it doesn't even get hit with the above code on Android 4.3 at least. I tried manually calling onPause() but that just renders my app into an invalid state.

Answer 1

To override the behavior of Back Button you can override onBackPressed() method in your Activity which is called when you press the back button:

@Override
public void onBackPressed() {
   moveTaskToBack(true);  // "Hide" your current Activity
}

By using moveTaskToBack(true) your Activity is sent to background but there is no guarantee it will remain in the "pause" state, Android can kill it if it needs memory. I don't know why you want this behavior I think it would be better to save Activity state and recover it when you are back or simply, launch another Intent with the new Activityyou want to bring.