Android press the return key again to exit the program implementation idea

private long exitTime = 0;
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK && () == KeyEvent.ACTION_DOWN){
if((()-exitTime) > 2000){
(getApplicationContext(), "Press again to exit the program", Toast.LENGTH_SHORT).show();
exitTime = ();
} else {
finish();
(0);
}
return true;
}
return (keyCode, event);
}