CountDown timer

CountDown.java

public class CountDown {
  
  private CountDownTimer countDownTimer;
  private int timeSeconds = 30;
  
  public CountDown(){
    countDownTimer = new CountDownTimer(timeSeconds * 1000, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                String v = String.format("%02d", millisUntilFinished / 60000);
                int va = (int) ((millisUntilFinished % 60000) / 1000);
                System.out.println(v + ":" + String.format("%02d", va));
            }

            @Override
            public void onFinish() {
              System.out.println("Finished");
            }
    };
  }
  
  public void startTimer(){
    countDownTimer.start();
  }
  
  public void stopTimer(){
    if (countDownTimer != null){
      countDownTimer.cancel();
    }
  }
  
}