/**

     * 倒数计时器

     */

    private CountDownTimer timer = new CountDownTimer(15 * 60 * 1000, 1000) {

        /**

         * 固定间隔被调用,就是每隔countDownInterval会回调一次方法onTick

         * @param millisUntilFinished

         */

        @Override

        public void onTick(long millisUntilFinished) {

            tv_remaining_time.setText(formatTime(millisUntilFinished));

        }

        /**

         * 倒计时完成时被调用

         */

        @Override

        public void onFinish() {

            tv_remaining_time.setText("00:00");

        }

    };

    /**

     * 将毫秒转化为 分钟：秒 的格式

     *

     * @param millisecond 毫秒

     * @return

     */

    public String formatTime(long millisecond) {

        int minute;//分钟

        int second;//秒数

        minute = (int) ((millisecond / 1000) / 60);

        second = (int) ((millisecond / 1000) % 60);

        if (minute < 10) {

            if (second < 10) {

                return "0" + minute + ":" + "0" + second;

            } else {

                return "0" + minute + ":" + second;

            }

        }else {

            if (second < 10) {

                return minute + ":" + "0" + second;

            } else {

                return minute + ":" + second;

            }

        }

    }

    /**

     * 取消倒计时

     */

    public void timerCancel() {

        timer.cancel();

    }

    /**

     * 开始倒计时

     */

    public void timerStart() {

        timer.start();

    }