更有效的Android秒表代码方法？

public long startTime = 0;
public void startTimer(View view) {
    Timer stopwatchTimer = new Timer();
    startTime = System.currentTimeMillis();
    stopwatchTimer.scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    TextView timerTextView = (TextView) findViewById(R.id.runningTimer);
                    timerTextView.setText(stopwatch());
                }
            });

        }
    }, 0, 10);
}

// Returns the combined string for the stopwatch, counting in tenths of seconds.
public String stopwatch() {
    long nowTime = System.currentTimeMillis();
    long cast = nowTime - startTime;
    Date date = new Date(cast);
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("HH:mm:ss.S");
    return simpleDateFormat.format(date);
}