android中的Handler

package com.wyl.wylhandler;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {
TextView tv;
Button btn;
Message msg;
Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView)findViewById(R.id.textViewId); //获取TextView
btn = (Button)findViewById(R.id.buttonId);	  //获取Button
myOnclickListener l = new myOnclickListener();//实例化一个监听器l
btn.setOnClickListener(l);					  //btn绑定上面获取的监听器l

}

class myOnclickListener implements OnClickListener{
@Override
public void onClick(View v) {
String c = "wyl";//设置断点用的
int len = c.length();//设置断点用的
System.out.println("len:"+len);
//1 .通过handler对象来获取message
myHandler myhandler = new myHandler();
msg = myhandler.obtainMessage();
String a = "zhang雅岚";//设置断点用的
msg.what = len;
msg.obj = a;
//handler sendMessage(msg)后，looper就自动从消息队列里取出msg(通过handleMessage方法),
myhandler.sendMessage(msg);	//handler把msg存入队列中
System.out.println("onClick所在线程："+Thread.currentThread().getName());
}	//调试发现，loop是在这一行的时候获取handler存入队列中的值msg
}

class myHandler extends Handler{
@Override
public void handleMessage(Message message) {
String name = "weiyongle";		//设置断点用的
int len2 = name.length();		//设置断点用的
System.out.println("len2:"+len2+","+"myHandler："+Thread.currentThread().getName());
Object obj = message.obj;
System.out.println("myHandler里打印出来："+obj+"myHandler所在线程："+Thread.currentThread().getName());

}
}

}