1 package com.example.m04_http01;
 2 
 3 import org.apache.http.HttpEntity;
 4 import org.apache.http.HttpResponse;
 5 import org.apache.http.client.HttpClient;
 6 import org.apache.http.client.methods.HttpGet;
 7 import org.apache.http.impl.client.DefaultHttpClient;
 8 import org.apache.http.util.EntityUtils;
 
 9 import android.app.Activity;
10 import android.os.Bundle;
11 import android.os.Handler;
12 import android.os.Message;
13 import android.view.View;
14 import android.view.View.OnClickListener;
15 import android.widget.Button;
16 import android.widget.TextView;
17 
18 public class MainActivity extends
 
 Activity {
19 
20     public static final int SHOW_RESPONSE = 0;
21     
22     private Button button_sendRequest;
23     private TextView textView_response;
24     
25     //新建Handler的物件，在這裡接收Message，然後更新TextView控制元件的內容
26     private Handler handler = new Handler() {
27 
28         @Override
29         public
 
 void handleMessage(Message msg) {
30             super.handleMessage(msg);
31             switch (msg.what) {
32             case SHOW_RESPONSE:
33                 String response = (String) msg.obj;
34                 textView_response.setText(response);
35                 break;
36 
37             default:
38                 break;
39             }            
40         }
41 
42     };
43     
44     @Override
45     protected void onCreate(Bundle savedInstanceState) {
46         super.onCreate(savedInstanceState);
47         setContentView(R.layout.activity_main);
48         textView_response = (TextView)findViewById(R.id.TextView1);
49         button_sendRequest = (Button)findViewById(R.id.button1);
50         
51         button_sendRequest.setOnClickListener(new OnClickListener() {
52             
53             //點選按鈕時，執行sendRequestWithHttpClient()方法裡面的執行緒
54             @Override
55             public void onClick(View v) {
56                 // TODO Auto-generated method stub
57                 sendRequestWithHttpClient();
58             }
59         });
60     }
61 
62     //方法：傳送網路請求，獲取百度首頁的資料。在裡面開啟執行緒
63     private void sendRequestWithHttpClient() {
64         new Thread(new Runnable() {
65             
66             @Override
67             public void run() {
68                 //用HttpClient傳送請求，分為五步
69                 //第一步：建立HttpClient物件
70                 HttpClient httpCient = new DefaultHttpClient();
71                 //第二步：建立代表請求的物件,引數是訪問的伺服器地址
72                 HttpGet httpGet = new HttpGet("http://www.baidu.com");
73                 
74                 try {
75                     //第三步：執行請求，獲取伺服器發還的相應物件
76                     HttpResponse httpResponse = httpCient.execute(httpGet);
77                     //第四步：檢查相應的狀態是否正常：檢查狀態碼的值是200表示正常
78                     if (httpResponse.getStatusLine().getStatusCode() == 200) {
79                         //第五步：從相應物件當中取出資料，放到entity當中
80                         HttpEntity entity = httpResponse.getEntity();
81                         String response = EntityUtils.toString(entity,"utf-8");//將entity當中的資料轉換為字串
82                         
83                         //在子執行緒中將Message物件發出去
84                         Message message = new Message();
85                         message.what = SHOW_RESPONSE;
86                         message.obj = response.toString();
87                         handler.sendMessage(message);
88                     }
89                     
90                 } catch (Exception e) {
91                     // TODO Auto-generated catch block
92                     e.printStackTrace();
93                 }
94                 
95             }
96         }).start();//這個start()方法不要忘記了        
97         
98     }    
99 }