Android中CountDownTimer实现倒计时功能

new CountDownTimer(6000,1000) {//第一个参数表示的是倒计时的总时间，第二参数表示的是倒计时的间隔时间。
          @Override
          public void onTick(long millisUntilFinished) {//倒计时的过程
            textView.setText(millisUntilFinished / 1000 + "秒");
          }

          @Override
          public void onFinish() {//倒计时结束
            textView.setText("倒计时结束");
          }
        }.start();

  /**
   * Cancel the countdown.
   */
  public synchronized final void cancel() {
    mCancelled = true;
    mHandler.removeMessages(MSG);
  }


 private static final int MSG = 1;


  // handles counting down
  private Handler mHandler = new Handler() {

    @Override
    public void handleMessage(Message msg) {

      synchronized (CountDownTimer.this) {
        if (mCancelled) {
          return;
        }

        final long millisLeft = mStopTimeInFuture - SystemClock.elapsedRealtime();

        if (millisLeft <= 0) {
          onFinish();
        } else if (millisLeft 

private boolean mCancelled = false;

 if (mCancelled) {
          return;
        }