android handler和looper

1 消息在主线程执行

handler = new Handler() {
  
  @Override public void handleMessage(Message msg) {

                          switch (msg.what) { 

                                 case R.string.hello: Log.i("tag", "this handler thread is " + Thread.currentThread().getName()); break;  
  default: break;

  }

 }  

  };

class ThreadWithMessage extends Thread {
Looper myLooper = null;


@Override
public void run() {
Log.i("tag", "the ThreadWithMessage is starting thread id is " + Thread.currentThread().getName()); 
  消息在不同线程间处理方法(消息在主线程中处理):

 Message message = new Message();

  message.what = R.string.hello;
  handler.sendMessage(message);

}
}

activity中的oncreate()方法中

// 消息在不同线程间处理方法(消息在主线程处理)
// Log.i("tag", "the main thread is" + Thread.currentThread().getName());
// new ThreadWithMessage().start();

消息在子线程执行

class ThreadWithMessage extends Thread {
Looper myLooper = null;
@Override
public void run() {
Log.i("tag", "the ThreadWithMessage is starting thread id is " + Thread.currentThread().getName());
// 实现线程间通信(消息在子线程中处理)
Looper.prepare();// 将looper 设置到这个线程中
myLooper = Looper.myLooper();
Looper.loop();// 开启消息循环
}
}

2 activity的onCreate()方法中

Log.i("tag", "the main thread is " + Thread.currentThread().getName());
// 消息在子线程处理
threadWithMessage = new ThreadWithMessage();
threadWithMessage.start();\

// 消息在子线程处理
Looper looper = threadWithMessage.myLooper;
handler = new Handler(looper) {


@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case R.string.hello:
Log.i("tag", "the handler thread is" + Thread.currentThread().getName());
break;


default:
break;
}
}


};
Message message = new Message();
message.what = R.string.hello;
handler.sendMessage(message);