Just a bit of advice needed really. I have an Activity running with my game in it and when the user presses the Back button it will exit back to the Main Menu using the onBa
Just an idea that might help you, i'm using it for my "home-made" ActionBar to determine when the user has actually arrived at the main (and last) activity before exiting. I start the Main-Activity manually and clear the whole activity stack by setting the FLAG_ACTIVITY_CLEAR_TOP flag, so if the user now hits the back button once again, the app is gonna get closed.
Intent intent = new Intent(getContext(), MainMenu.class).
setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);