android 三种定时器的写法

一、 使用Timer 和 TimerTask
Timer timer = new Timer();
MyTimerTask timerTask = new MyTimerTask();
timer.schedule(timerTask, 3000, 1); // 延迟3秒钟,执行1次
//timer.cancel();// 取消

class MyTimerTask extends TimerTask {
    @Override
    public void run() {
                //这里不能处理UI操作
        // do something
    }
}
    
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二、采用Handler的sendMessageDelayed(Message, long)
public void startAutoFlowTimer() {
    handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            // do something

            Message message = handler.obtainMessage(0);
            sendMessageDelayed(message, 1000);
        }
    };

    Message message = handler.obtainMessage(0);
    handler.sendMessageDelayed(message, 1000);
}

handler.removeMessages(0) //结束调用

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三、采用Handler的postDelayed(Runnable, long) 方法,这个实现比较简单一些：
1. Handler handler=new Handler();
Runnable runnable=new Runnable(){
    @Override
    public void run() {
        // do something
        handler.postDelayed(this, 2000); //在这里实现每两秒执行一次
    }
};

handler.postDelayed(runnable, 2000);//启动,两秒后执行runnable.

handler.removeCallbacks(runnable);  //停止

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//延迟执行
// 设置异步线程,
Handler handler = new Handler() {
    public void handleMessage(Message msg) { // handle message
        switch (msg.what) {
        case 1:
            //ui 方法
        }
        super.handleMessage(msg);
    }
};

Message message = handler.obtainMessage(1);
handler.sendMessageDelayed(message, 3000); // 发送message,3秒后隐藏提示框