Doeble Tab to Close Your Apps

you can copy this code to your project

boolean doubleBackToExitPressedOnce = false;@Overridepublic void onBackPressed() {
    if (doubleBackToExitPressedOnce) {
        super.onBackPressed();        return;    }

    this.doubleBackToExitPressedOnce = true;    Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
    new Handler().postDelayed(new Runnable() {

        @Override        public void run() {
            doubleBackToExitPressedOnce=false;        }
    }, 2000);}