Androidの多线程之Handler创建新线程

两个Handler，一个是主线程的mainHandler，一个是获取HandlerThread的looper的Handler.

mainHandler在新线程发出消息，在主线程处理接受的消息。

looperHandler拥有looper后即可post(Runnable)，发起新线程，然后通过mainHandler在新线程里发送消息到主线程的handler。

这里创建两个handler，一个是mainHandler维护主线程的looper,一个是looperHandler拥护HandlerThread的looper。

1.mainHandler处理消息，复写handlerMessage()方法处理消息。

2.looperHandler应通过HandlerThread获取looper来构造，而且HandlerThread必须开启，否则得不到looper。

3.looperHandler来post一个runnable对象，在runnable里复写run()方法，在里面用mainHandler发送方消息。

 1 package com.bvin.handler;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.os.Handler;
 6 import android.os.HandlerThread;
 7 import android.os.Message;
 8 import android.util.Log;
 9 import android.view.View;
10 import android.widget.Button;
11 import android.widget.LinearLayout;
12 import android.widget.LinearLayout.LayoutParams;
13 import android.widget.TextView;
14 
15 public class MainActivity extends Activity {
16     /** Called when the activity is first created. */
17     
18     private Handler loopHandler ;
19     private Handler mainHandler; 
20     private TextView tv;
21     @Override
22     public void onCreate(Bundle savedInstanceState) {
23         super.onCreate(savedInstanceState);
24         
25         initViews();
26         HandlerThread ht = new HandlerThread("handler thread");
27         ht.start();//loopHandler的runnable这里先开始le，而mainHandler是点击之后
28         loopHandler = new Handler(ht.getLooper());
29         mainHandler= new Handler(){
30 
31             @Override
32             public void handleMessage(Message msg) {
33                 // TODO Auto-generated method stub
34                 super.handleMessage(msg);
35                 if(msg.what==2012){
36                     
37                     tv.setText(msg.getData().getString("s"));
38                 }
39                 
40             }
41         };
42     }
43     
44     
45     private void initViews(){
46         
47         LinearLayout layout = new LinearLayout(this);
48         layout.setOrientation(LinearLayout.VERTICAL);
49         LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT);
50         tv = new TextView(this);
51         tv.setText("本来");
52         Button bt = new Button(this);
53         
54         bt.setText("开动");
55         bt.setOnClickListener(new View.OnClickListener() {
56             
57             @Override
58             public void onClick(View v) {
59                 // TODO Auto-generated method stub
60                 mainHandler.post(new Runnable(){
61 
62                     @Override
63                     public void run() {
64                         // TODO Auto-generated method stub
65                         Log.e("mainHandler所在当前线程", ""+Thread.currentThread().getName());
66                         //tv.setText("对不对");
67                     }
68                 });
69                  
70                 loopHandler.post(new Runnable(){
71 
72                     @Override
73                     public void run() {
74                         // TODO Auto-generated method stub
75                         Log.e("loopHandler所在当前线程", ""+Thread.currentThread().getName());
76                         Message msg = mainHandler.obtainMessage();
77                         msg.what = 2012;
78                         Bundle bundle = new Bundle();
79                         bundle.putString("s", "从"+Thread.currentThread().getName()+"线程传过来的");
80                         msg.setData(bundle);
81                         msg.sendToTarget();
82                     }
83                 });
84                 
85             }
86         });
87         layout.addView(bt,params);
88         layout.addView(tv,params);
89         setContentView(layout);
90         
91     }
92 }