android timer倒计时

private Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            int arg1 = msg.arg1;
            if (arg1 == 0) {//时间到
                
            }
            textView.setText(String.valueOf(arg1));
        }
    };
 
    /**
     * 开始自动减时
     */
    private void startTime() {
        if (timer == null) {
            timer = new Timer();
        }
 
        timerTask = new TimerTask() {
 
            @Override
            public void run() {
 
                Message message = Message.obtain();
                message.arg1 = time;
                mHandler.sendMessage(message);//发送消息
 
                time--;//自动减1
 
            }
        };
        timer.schedule(timerTask, 0, 1000);//1000ms执行一次
    }
 

    private void stopTime() {
        if (timer != null) {
            timer.cancel();
            timer = null;
        }
 
        if (timerTask != null) {
            timerTask.cancel();
            timerTask = null;
        }
        time = 0;
 
    }