countDown timer in android

 How to use countdown timer in android? It's very easy. There a CountDownTimer class in android, For example:

2. new CountDownTimer(30000, 1000) {
3. 
   
4.     public void onTick(long millisUntilFinished) {
5.          mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
6.     }
7. 
   
8.     public void onFinish() {
9.          mTextField.setText("done!");
10.     }
11. 
    
12. }.start();