Back 두번눌러서 종료시키기

//상단에 선언  private boolean isTwoClickBack = false; . . @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {   if(event.getAction() == KeyEvent.ACTION_DOWN){    if(keyCode == KeyEvent.KEYCODE_BACK){     if(!isTwoClickBack){      Toast.makeText(this, "'뒤로'버튼을 한번더 클릭 하시면 종료됩니다." , Toast.LENGTH_SHORT).show();      CntTimer timer = new CntTimer(2000, 1);      timer.start();     }else{      finish();      return true;     }         }   }   return false;  } . class CntTimer extends CountDownTimer{   public CntTimer(long millisInFuture, long countDownInterval) {    super(millisInFuture, countDownInterval);    isTwoClickBack = true;   }   @Override   public void onFinish() {    // TODO Auto-generated method stub    isTwoClickBack = false;   }   @Override   public void onTick(long millisUntilFinished) {    // TODO Auto-generated method stub    Log.i("Test"," isTwoClickBack " + isTwoClickBack);   }           }