[移动开发]Android 简单的计时器（格式为：00:15:13）

1.新建 Handler

 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        mHandler = new Handler(getMainLooper());
        mHandler.post(mTimerRunable);
    }

2.执行runable

    private Runnable mTimerRunable = new Runnable() {
        private int hour, minute, second;
        @Override
        public void run() {
            ++second;
            minute = second == 60 ? ++minute : minute;
            hour = minute == 60 ? ++hour : hour;
            second = second == 60 ? 0 : second;
            textview.setText(String.format("%02d:%02d:%02d", hour, minute, second));
            mHandler.postDelayed(this, 1000);
        }
    };

3.移除 runable

mHandler.removeCallbacks(mTimerRunable);