onPause not called when back button pressed?

Question

It was my understanding, obviously wrong, that onPause() is called whenever the back button is pressed? Now in my code I've put this onPause() event:

@Override
protected void onPause(){
    super.onPause();        

    if(!_END_GAME){
        Builder _alert = new AlertDialog.Builder(this)
        .setMessage("onPause, with game NOT over!");
        _alert.setNeutralButton("OK.",
                new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                arg0.dismiss(); // Kills the interface
                System.runFinalizersOnExit(true);
                finish();
            }
        });
        _alert.setTitle("Your Score!");
        _alert.show();
    }

}

Now the problem is, the dialog does not launch what-so-ever, and then the code errors out. I put the dialog there to try to visualize where the onPause( ) was called and help me debug some other variables and such. Yet like I said it never even gets shown. Any ideas why this would be? Is there a function that is launched prior to onPause() when the back button is pressed? Thank you in advance for any info.

Answer 1

onPause will always be called when your activity is no longer in the foreground, that's guaranteed. Maybe your _END_GAME is not false? Add a debug log output to your onPause method, you'll see that it always gets called.

I should note though that displaying a dialog during onPause is extremely bad form - the user is trying to get rid of your app (could even be because of an incoming phone call). You DO NOT want a dialog then. That goes against the Android design.

In fact, the Android OS will simply short-circuit your app if you try to do lengthy shenanigans in onDestroy or onPause. Basically, if those get called, you're supposed to disappear quietly.

If you really want to intercept the back button, you can check for the button like Ted suggested, but keep in mind that your app can go to the background in many other ways - home button, selected notification, incoming phone call, etc.

Answer 2

You should check for the back button by overriding onKeyDown , not testing in onPause . onPause gets called whenever your activity is no longer in the background leaves the foreground; it is not necessarily finishing. (You can check isFinishing() for that.) See here for more info on handling the back key.

Answer 3

onPause is getting called, and your dialog is showing, just for a tiny split-second before Android finishes your app. Put log statements in there if you want to watch what is going on.

If you want to show a dialog when the back button is pressed then the easiest way (works on Android 2.1+) is to override the onBackPressed method in your activity

@Override
public void onBackPressed() {
    if (gameRunning) {
        // show dialog
    } else {
        // exit
        super.onBackPressed();
    }
}