倒计时秒数卡着不动该怎么修改

private void starttime() {
timer = new Timer();
task = new TimerTask() {

        @Override
        public void run() {
            if (i > 0) {
              //  i--;
                i1=i*60;
                i1--;
                    int h=i1/3600;
                    int m=i1%3600/60;
                    int s=i1%3600%60;
                    String H,M,S;

                    if (h<10){
                        H="0"+h;
                    }else
                        H=h+"";
                    if (m<10){
                        M="0"+m;
                    }
                    else
                        M=m+"";
                    if(s<10){
                        S=s+"0";
                    }else
                        S=s+"";
                    String show= H+":"+M+":"+S;
                Message message = mHandler1.obtainMessage();
                message.obj = show;
                mHandler1.sendMessage(message);

            }
        }
    };
    timer.schedule(task, 1000);
}

public void stoptime(){
    timer.cancel();
}

你这个代码逻辑有点问题，我发个例子给你参考一下。