Android實現定時器3種方式，現將三種方式寫在一個類裡，對比參考：

/**
 * @author huihui 三種計時器
 */
public abstract class MyTimer {
    private int count = 0; // 計時器執行次數
    private int type = 1; // 1表示handle+Thread,2表示handle的postdelay,3表示TimeTask
    private int duration = 0; // 計時器時間間隔
    private boolean flg1 = false; // 計時器1標記
    private
 
 Timer timer;
    Handler myHandler;

    public abstract void onTick();

    public MyTimer() {
        count = 0;

        myHandler = new Handler() {

            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);

                switch (msg.what) {
                case
 
 0x123:
                    count++;
                    onTick();
                    break;

                default:
                    break;
                }
            }

        };
    }

    public int getCount() {
        return count;
    }

    public void start(int type, int duration) {
        stop();
        count = 0
 
;
        this.type = type;
        this.duration = duration;

        switch (type) {
        case 1: // 啟動計時器1
            flg1 = true;
            new Thread(new MyThread()).start();
            break;

        case 2:
            myHandler.postDelayed(runnable, duration);
            break;

        case 3:
            timer = new Timer();
            /**
             * 第三種計時器方式， timerTask
             */
            TimerTask task = new TimerTask() {

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    myHandler.sendEmptyMessage(0x123);
                }
            };
            timer.schedule(task, duration, duration);
            break;

        default:
            break;
        }

    }

    public void stop() { // 停止計時器
        flg1 = false;
        switch (type) {
        case 2:
            myHandler.removeCallbacks(runnable);
            break;

        case 3:
            timer.cancel();
            break;

        default:
            break;
        }
    }

    /**
     * 第二種計時器方式 handle postdelay
     */
    private Runnable runnable = new Runnable() {

        @Override
        public void run() {
            // TODO Auto-generated method stub
            myHandler.postDelayed(this, duration);
            count++;
            onTick();
        }
    };

    /**
     * @author huihui 第一種計時器方式， handle+thread
     */
    class MyThread implements Runnable {

        @Override
        public void run() {
            while (flg1) {
                try {
                    Thread.sleep(duration);
                    myHandler.sendEmptyMessage(0x123);
                }
                catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }

        }

    }
}

另還有系統倒計時CountDownTimer類，此類可實現倒計時功能，並在固定間隔收到通知。

    CountDownTimer countDownTimer = new CountDownTimer() {

        @Override
        public void onTick(long millisUntilFinished) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onFinish() {
            // TODO Auto-generated method stub

        }
    };

其中OnTick的呼叫是同步的，即前一次呼叫處理完了才有可能處理下一次呼叫。如果處理時間超過OnTick間隔，會漏掉OnTick通知。