Press Back Twice To Exit Game - Android Back Button

Hi Boxers, I'm trying to implement a "press twice to exit" behavior for the back button on Android devices. I'm experiencing different results when pressing the back button on my game: sometimes it goes back to the previous screen, sometimes it exits the game and sometimes it does nothing and then opens a recent opened app .
What I'm trying to achieve is having the back button display a toast message like "Press again to exit" on all my game screens, so I don't have to deal with the back button. I've seen this behavior in games like Wall Switch.

I tried following the example below and modify my PTPlayer java file but I cannot get it working, and my Android knowledge is limited.
Any help is appreciated. Thanks!

Here's my code:

Code:

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        this.hideVirtualButton();

        PTServicesBridge.initBridge(this, getString( R.string.app_id ));
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    }

// Press twice to exit

    private static final int TIME_LIMIT = 1500;
    private static long backPressed;

    @Override
    public void onBackPressed() {

        if (TIME_LIMIT + backPressed > System.currentTimeMillis()){
            super.onBackPressed();
        }
        else {
            Toast.makeText(getApplicationContext(), "Press again to exit",Toast.LENGTH_SHORT).show();
        }
        backPressed = System.currentTimeMillis();

    }
    

Here's the example:

 

At least your app is responding something there is no results on the implimeting code.