Android handler实现线程间通信

最新推荐文章于 2025-07-02 10:28:03 发布

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本文展示了一个Android环境中多线程间通过Handler进行消息传递的例子。主要包括主线程与其他两个子线程之间的消息交互过程，涉及Looper.prepare()及Looper.loop()的使用。

先上代码：

//主线程的handler

private Handler mHandler = new Handler(){

@Override
public void handleMessage(Message msg)
{
super.handleMessage(msg);
System.out.println("this is response from main thread " + Thread.currentThread().getId());
handler2.sendEmptyMessage(0);
}};
//线程1handler

private Handler handler1;

//线程2handler

private Handler handler2;

//子线程1

private Thread thread1 = new Thread()
{
@Override
public void run()

{

super.run();

//子线程中实现handler必须先调用Looper.prepare();否则会抛出异常

Looper.prepare();
handler1 = new Handler()//这里也可以使用Handler(Looper.mylooper())
{
@Override
public void handleMessage(Message msg)
{
super.handleMessage(msg);

// mHandler.sendEmptyMessage(0);//向主线程发消息

// handler2.sendEmptyMessage(0);//线程2发消息

System.out.println("this is response from handler1 in thread1 " + Thread.currentThread().getId());
}

};

//启动子线程的消息循环队列

Looper.loop();

}

};

//子线程2

private Thread thread2 = new Thread()
{

@Override
public void run()
{
super.run();
Looper.prepare();
handler2 = new Handler()
{
@Override
public void handleMessage(Message msg)
{
super.handleMessage(msg);
handler1.sendEmptyMessage(0);//线程1发消息
System.out.println("this is response from handler2 in thread2 " + Thread.currentThread().getId());
}

};

Looper.loop();
}

};

测试代码：thread1.start();
thread2.start();
mHandler.sendEmptyMessage(0);

打印结果

I/System.out(26814): this is response from main thread 1
I/System.out(26814): this is response from handler2 in thread28050
I/System.out(26814): this is response from handler1 in thread18049