类似于标题栏中倒计时的样式：

倒计时.png

自定义CountDownTimer

    class MyCountDown extends CountDownTimer{

        public MyCountDown(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onTick(long millisUntilFinished) {
            minute = (int) (millisUntilFinished/60000);
            second--;
            if(second<0){
                second = 59;
            }
            showTimeStr();
        }

        @Override
        public void onFinish() {
            second = 0;
            showTimeStr();
            //提交
        }
    }

初始化，调用

    private int minute,second;

        minute = 5;
        second = 0;
        countDown = new MyCountDown(60000*minute,1000);
        countDown.start();

textview的刷新

    private void showTimeStr() {
        String time = new String();
        if(second/10>0){
            time = minute+":"+second;
        }else{
            time = minute+":0"+second;
        }
        tvChallengeTime.setText(time);

    }