主线程向子线程发送数据

package com.example.zjday18_handler_03;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.View;
/**
 * 主线程向子线程发送数据
 * @author Administrator
 *
 */
public class MainActivity extends Activity {

private Handler handler;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//开启子线程
new connectThread().start();
    }

public void sendMessage(View v){
if(handler!=null){
            Message msg =Message.obtain();
            msg.obj ="向子线程中发送数据！";
            handler.sendMessage(msg);
        }
    }

//子线程
    class connectThread extends Thread{
@Override
public void run() {
//1.创建Looper对象
            Looper.prepare();
//2.实例化Handler
            handler =new Handler(){
public void handleMessage(Message msg) {
//接受主线程发送过来的消息
super.handleMessage(msg);
                    String info =(String) msg.obj;
                    Log.i("---", info);
                };
            };
//3.循环读取MessageQueue
            Looper.loop();
        }
    }
}