Android 定时器

1.Handler类的postDelayed方法：

  final Handler mHandler = new Handler();
    Runnable r = new Runnable() {

        @Override
        public void run() {
            //do something
            //每隔1s循环执行run方法
            mHandler.postDelayed(this, 1000);
        }
    };

    //主线程中调用：
    mHandler.postDelayed(r, 100);//延时100毫秒

2.用handler+timer+timeTask方法：

final Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 1) {
                //do something
            }
            super.handleMessage(msg);
        }
    };

    Timer timer = new Timer();
    TimerTask timerTask = new TimerTask() {
        @Override
        public void run() {
            Message message = new Message();
            message.what = 1;
            handler.sendMessage(message);
        }
    };

     //主线程中调用：
    timer.schedule(timerTask, 1000, 500);//延时1s，每隔500毫秒执行一次run方法

3.Thread+handler方法：

final Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 1) {
                //do something
            }
            super.handleMessage(msg);

        }
    };

    class MyThread extends Thread {//这里也可用Runnable接口实现

        @Override
        public void run() {
            while (true) {
                try {
                    Thread.sleep(1000);//每隔1s执行一次
                    Message msg = new Message();
                    msg.what = 1;
                    handler.sendMessage(msg);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }
    }
    //主线程中调用：
    new Thread(new MyThread()).start();
1.Handler的postDelayed方法：

new Handler().postDelayed(new Runnable() {

    @Override
    public void run() {
        //do something
    }
}, 1000);    //延时1s执行

2.timer + TimerTask方法：

Timer timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
//do something
}
},1000);//延时1s执行

3.Thread方法：

new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(1000);//延时1s
//do something
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}).start();
CountDownTimer countDownTimer = new CountDownTimer(totalTime, 2000) {
@Override
public void onTick(long millisUntilFinished) {
updateFileData(fileId); //执行任务
}

        @Override
        public void onFinish() {
            if (User.getInstance().isLoginIng()) {
                if (countDownTimer != null) {
                    countDownTimer.start();
                }
            }
        }
    };
    countDownTimer.start();