CountDownTimer

代码片.

// An highlighted block
	private MyCountDownTimer  timer;
	private final long TIME = 7 * 1000L;
	private final long INTERVAL = 1000L;
	private  class  MyCountDownTimer extends CountDownTimer{
		/**
		 * @param millisInFuture    The number of millis in the future from the call
		 *                          to {@link #start()} until the countdown is done and {@link #onFinish()}
		 *                          is called.
		 * @param countDownInterval The interval along the way to receive
		 *                          {@link #onTick(long)} callbacks.
		 */
		public MyCountDownTimer(long millisInFuture, long countDownInterval) {
			super(millisInFuture, countDownInterval);
		}

		@Override
		public void onTick(long millisUntilFinished) {
			long time = millisUntilFinished / 1000;
			Log.e("wuzhang",time+"秒");
		}

		@Override
		public void onFinish() {
			cancelTimer();
			adsAPI.startAds(QRSuccessActivity.this, adRequest);
			finish();
		}
	}
	/**
	 * 开始倒计时
	 */
	private void startTimer() {
		if (timer == null) {
			timer = new MyCountDownTimer(TIME, INTERVAL);
		}
		timer.start();
	}

	/**
	 * 取消倒计时
	 */
	private void cancelTimer() {
		if (timer != null) {
			timer.cancel();
			timer = null;
		}
	}

使用

代码片.

@Override
	protected void onCreate(Bundle savedInstanceState) {
	startTimer();
	.......
}

@Override
	protected void onDestroy() {
		super.onDestroy();
		cancelTimer();
	}