使用 Handler 建立一個 Timer（類似於 javax.swing.Timer）

如果你正在編寫遊戲或需要每隔幾秒鐘執行一段程式碼的內容，這將非常有用。

import android.os.Handler;

public class Timer {
    private Handler handler;
    private boolean paused;

    private int interval;

    private Runnable task = new Runnable () {
        @Override
        public void run() {
            if (!paused) {
                runnable.run ();
                Timer.this.handler.postDelayed (this, interval);
            }
        }
    };

    private Runnable runnable;

    public int getInterval() {
        return interval;
    }

    public void setInterval(int interval) {
        this.interval = interval;
    }

    public void startTimer () {
        paused = false;
        handler.postDelayed (task, interval);
    }

    public void stopTimer () {
        paused = true;
    }

    public Timer (Runnable runnable, int interval, boolean started) {
        handler = new Handler ();
        this.runnable = runnable;
        this.interval = interval;
        if (started)
            startTimer ();
    }
}

用法示例：

Timer timer = new Timer(new Runnable() {
    public void run() {
        System.out.println("Hello");
    }
}, 1000, true)

此程式碼將每秒列印 Hello。