int second = 0；

Handler handler = new Handler();        handler.post(runnable);Runnable runnable = new Runnable() {        @Override        public void run() {            second++;            patrol_time_txt.setText(Util.getTime(second));            handler.postDelayed(runnable, 1000);        }    };

//根据秒数转化为时分秒   00:00:00
public static String getTime(int second) {        if (second < 10) {            return "00:0" + second;        }        if (second < 60) {            return "00:" + second;        }        if (second < 3600) {            int minute = second / 60;            second = second - minute * 60;            if (minute < 10) {                if (second < 10) {                    return "0" + minute + ":0" + second;                }                return "0" + minute + ":" + second;            }            if (second < 10) {                return minute + ":0" + second;            }            return minute + ":" + second;        }        int hour = second / 3600;        int minute = (second - hour * 3600) / 60;        second = second - hour * 3600 - minute * 60;        if (hour < 10) {            if (minute < 10) {                if (second < 10) {                    return "0" + hour + ":0" + minute + ":0" + second;                }                return "0" + hour + ":0" + minute + ":" + second;            }            if (second < 10) {                return "0" + hour + minute + ":0" + second;            }            return "0" + hour + minute + ":" + second;        }        if (minute < 10) {            if (second < 10) {                return hour + ":0" + minute + ":0" + second;            }            return hour + ":0" + minute + ":" + second;        }        if (second < 10) {            return hour + minute + ":0" + second;        }        return hour + minute + ":" + second;    }