一、概述
關於Socket編程的基本方法在基礎篇里已經講過，今天把它給完善了。加入了多線程，這樣UI線程就不會被阻塞；實現了客戶端和服務器的雙向通信，只要客戶端發起了連接並成功連接后那么兩者就可以隨意進行通信了。
二、實現
在之前的工程基礎上進行修改就可以了。
MyClient工程的main.xml文件不用修改，只需要修改MyClientActivity.java文件，主要是定義了一個繼承自Thread類的用於接收數據的類，覆寫了其中的run（）方法，在這個函數里面接收數據，接收到數據后就通過Handler發送消息，收到消息后在UI線程里更新接收到的數據。完整的內容如下：
1 package com.nan.client;
2
3 import java.io.IOException;
4 import java.io.InputStream;
5 import java.io.OutputStream;
6 import java.io.UnsupportedEncodingException;
7 import java.net.Socket;
8 import java.net.UnknownHostException;
9
10 import android.app.Activity;
11 import android.os.Bundle;
12 import android.os.Handler;
13 import android.os.Message;
14 import android.view.View;
15 import android.widget.Button;
16 import android.widget.EditText;
17 import android.widget.TextView;
18 import android.widget.Toast;
19
20
21 public class MyClientActivity extends Activity
22 {
23 private EditText mEditText = null;
24 private Button connectButton = null;
25 private Button sendButton = null;
26 private TextView mTextView = null;
27
28 private Socket clientSocket = null;
29 private OutputStream outStream = null;
30
31 private Handler mHandler = null;
32
33 private ReceiveThread mReceiveThread = null;
34 private boolean stop = true;
35
36 /** Called when the activity is first created. */
37 @Override
38 public void onCreate(Bundle savedInstanceState)
39 {
40 super.onCreate(savedInstanceState);
41 setContentView(R.layout.main);
42
43 mEditText = (EditText)this.findViewById(R.id.edittext);
44 mTextView = (TextView)this.findViewById(R.id.retextview);
45 connectButton = (Button)this.findViewById(R.id.connectbutton);
46 sendButton = (Button)this.findViewById(R.id.sendbutton);
47 sendButton.setEnabled(false);
48
49 //連接按鈕監聽
50 connectButton.setOnClickListener(new View.OnClickListener()
51 {
52
53 @Override
54 public void onClick(View v)
55 {
56 // TODO Auto-generated method stub
57 try
58 {
59 //實例化對象並連接到服務器
60 clientSocket = new Socket("113.114.170.246",8888);
61 }
62 catch (UnknownHostException e)
63 {
64 // TODO Auto-generated catch block
65 e.printStackTrace();
66 }
67 catch (IOException e)
68 {
69 // TODO Auto-generated catch block
70 e.printStackTrace();
71 }
72
73 displayToast("連接成功！");
74 //連接按鈕使能
75 connectButton.setEnabled(false);
76 //發送按鈕使能
77 sendButton.setEnabled(true);
78
79 mReceiveThread = new ReceiveThread(clientSocket);
80 stop = false;
81 //開啟線程
82 mReceiveThread.start();
83 }
84 });
85
86 //發送數據按鈕監聽
87 sendButton.setOnClickListener(new View.OnClickListener()
88 {
89
90 @Override
91 public void onClick(View v)
92 {
93 // TODO Auto-generated method stub
94 byte[] msgBuffer = null;
95 //獲得EditTex的內容
96 String text = mEditText.getText().toString();
97 try {
98 //字符編碼轉換
99 msgBuffer = text.getBytes("GB2312");
100 } catch (UnsupportedEncodingException e1) {
101 // TODO Auto-generated catch block
102 e1.printStackTrace();
103 }
104
105
106 try {
107 //獲得Socket的輸出流
108 outStream = clientSocket.getOutputStream();
109 } catch (IOException e) {
110 // TODO Auto-generated catch block
111 e.printStackTrace();
112 }
113
114
115 try {
116 //發送數據
117 outStream.write(msgBuffer);
118 } catch (IOException e) {
119 // TODO Auto-generated catch block
120 e.printStackTrace();
121 }
122 //清空內容
123 mEditText.setText("");
124 displayToast("發送成功！");
125 }
126 });
127
128 //消息處理
129 mHandler = new Handler()
130 {
131 @Override
132 public void handleMessage(Message msg)
133 {
134 //顯示接收到的內容
135 mTextView.setText((msg.obj).toString());
136 }
137 };
138
139 }
140
141 //顯示Toast函數
142 private void displayToast(String s)
143 {
144 Toast.makeText(this, s, Toast.LENGTH_SHORT).show();
145 }
146
147
148 private class ReceiveThread extends Thread
149 {
150 private InputStream inStream = null;
151
152 private byte[] buf;
153 private String str = null;
154
155 ReceiveThread(Socket s)
156 {
157 try {
158 //獲得輸入流
159 this.inStream = s.getInputStream();
160 } catch (IOException e) {
161 // TODO Auto-generated catch block
162 e.printStackTrace();
163 }
164 }
165
166 @Override
167 public void run()
168 {
169 while(!stop)
170 {
171 this.buf = new byte[512];
172
173 try {
174 //讀取輸入數據（阻塞）
175 this.inStream.read(this.buf);
176 } catch (IOException e) {
177 // TODO Auto-generated catch block
178 e.printStackTrace();
179 }
180
181 //字符編碼轉換
182 try {
183 this.str = new String(this.buf, "GB2312").trim();
184 } catch (UnsupportedEncodingException e) {
185 // TODO Auto-generated catch block
186 e.printStackTrace();
187 }
188
189 Message msg = new Message();
190 msg.obj = this.str;
191 //發送消息
192 mHandler.sendMessage(msg);
193
194 }
195 }
196
197
198 }
199
200 @Override
201 public void onDestroy()
202 {
203 super.onDestroy();
204
205 if(mReceiveThread != null)
206 {
207 stop = true;
208 mReceiveThread.interrupt();
209 }
210 }
211
212 }
對於MyServer工程，改動比較大，首先是main.xml文件，在里面添加了兩個TextView，一個用於顯示客戶端的IP，一個用於顯示接收到的內容，一個用於發送數據的Button，還有一個EditText，完整的main.xml如下：
1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 android:layout_width="fill_parent"
4 android:layout_height="fill_parent"
5 android:orientation="vertical" >
6
7 <TextView
8 android:id="@+id/iptextview"
9 android:layout_width="fill_parent"
10 android:layout_height="wrap_content"
11 android:textSize="20dip"
12 android:gravity="center_horizontal"
13 />
14
15 <EditText
16 android:id="@+id/sedittext"
17 android:layout_width="fill_parent"
18 android:layout_height="wrap_content"
19 android:hint="請輸入要發送的內容"
20 />
21
22 <Button
23 android:id="@+id/sendbutton"
24 android:layout_width="fill_parent"
25 android:layout_height="wrap_content"
26 android:text="發送"
27 />
28
29 <TextView
30 android:id="@+id/textview"
31 android:layout_width="fill_parent"
32 android:layout_height="wrap_content"
33 android:textSize="15dip"
34
35 />
36
37 </LinearLayout>
接着，修改MyServerActivity.java文件，定義了兩個Thread子類，一個用於監聽客戶端的連接，一個用於接收數據，其他地方與MyClientActivity.java差不多。完整的內容如下：
1 package com.nan.server;
2
3 import java.io.IOException;
4 import java.io.InputStream;
5 import java.io.OutputStream;
6 import java.io.UnsupportedEncodingException;
7 import java.net.ServerSocket;
8 import java.net.Socket;
9
10 import android.app.Activity;
11 import android.os.Bundle;
12 import android.os.Handler;
13 import android.os.Message;
14 import android.view.View;
15 import android.widget.Button;
16 import android.widget.EditText;
17 import android.widget.TextView;
18 import android.widget.Toast;
19
20
21 public class MyServerActivity extends Activity
22 {
23 private TextView ipTextView = null;
24 private EditText mEditText = null;
25 private Button sendButton = null;
26 private TextView mTextView = null;
27
28 private OutputStream outStream = null;
29 private Socket clientSocket = null;
30 private ServerSocket mServerSocket = null;
31
32 private Handler mHandler = null;
33
34 private AcceptThread mAcceptThread = null;
35 private ReceiveThread mReceiveThread = null;
36 private boolean stop = true;
37
38 /** Called when the activity is first created. */
39 @Override
40 public void onCreate(Bundle savedInstanceState)
41 {
42 super.onCreate(savedInstanceState);
43 setContentView(R.layout.main);
44
45 ipTextView = (TextView)this.findViewById(R.id.iptextview);
46 mEditText = (EditText)this.findViewById(R.id.sedittext);
47 sendButton = (Button)this.findViewById(R.id.sendbutton);
48 sendButton.setEnabled(false);
49 mTextView = (TextView)this.findViewById(R.id.textview);
50
51 //發送數據按鈕監聽
52 sendButton.setOnClickListener(new View.OnClickListener()
53 {
54
55 @Override
56 public void onClick(View v)
57 {
58 // TODO Auto-generated method stub
59 byte[] msgBuffer = null;
60 //獲得EditTex的內容
61 String text = mEditText.getText().toString();
62 try {
63 //字符編碼轉換
64 msgBuffer = text.getBytes("GB2312");
65 } catch (UnsupportedEncodingException e1) {
66 // TODO Auto-generated catch block
67 e1.printStackTrace();
68 }
69
70
71 try {
72 //獲得Socket的輸出流
73 outStream = clientSocket.getOutputStream();
74 } catch (IOException e) {
75 // TODO Auto-generated catch block
76 e.printStackTrace();
77 }
78
79
80 try {
81 //發送數據
82 outStream.write(msgBuffer);
83 } catch (IOException e) {
84 // TODO Auto-generated catch block
85 e.printStackTrace();
86 }
87 //清空內容
88 mEditText.setText("");
89 displayToast("發送成功！");
90
91 }
92 });
93 //消息處理
94 mHandler = new Handler()
95 {
96 @Override
97 public void handleMessage(Message msg)
98 {
99 switch(msg.what)
100 {
101 case 0:
102 {
103 //顯示客戶端IP
104 ipTextView.setText((msg.obj).toString());
105 //使能發送按鈕
106 sendButton.setEnabled(true);
107 break;
108 }
109 case 1:
110 {
111 //顯示接收到的數據
112 mTextView.setText((msg.obj).toString());
113 break;
114 }
115 }
116
117 }
118 };
119
120
121 mAcceptThread = new AcceptThread();
122 //開啟監聽線程
123 mAcceptThread.start();
124
125 }
126
127 //顯示Toast函數
128 private void displayToast(String s)
129 {
130 Toast.makeText(this, s, Toast.LENGTH_SHORT).show();
131 }
132
133
134 private class AcceptThread extends Thread
135 {
136 @Override
137 public void run()
138 {
139 try {
140 //實例化ServerSocket對象並設置端口號為8888
141 mServerSocket = new ServerSocket(8888);
142 } catch (IOException e) {
143 // TODO Auto-generated catch block
144 e.printStackTrace();
145 }
146
147 try {
148 //等待客戶端的連接（阻塞）
149 clientSocket = mServerSocket.accept();
150 } catch (IOException e) {
151 // TODO Auto-generated catch block
152 e.printStackTrace();
153 }
154
155 mReceiveThread = new ReceiveThread(clientSocket);
156 stop = false;
157 //開啟接收線程
158 mReceiveThread.start();
159
160 Message msg = new Message();
161 msg.what = 0;
162 //獲取客戶端IP
163 msg.obj = clientSocket.getInetAddress().getHostAddress();
164 //發送消息
165 mHandler.sendMessage(msg);
166
167 }
168
169 }
170
171
172 private class ReceiveThread extends Thread
173 {
174 private InputStream mInputStream = null;
175 private byte[] buf ;
176 private String str = null;
177
178 ReceiveThread(Socket s)
179 {
180 try {
181 //獲得輸入流
182 this.mInputStream = s.getInputStream();
183 } catch (IOException e) {
184 // TODO Auto-generated catch block
185 e.printStackTrace();
186 }
187 }
188
189 @Override
190 public void run()
191 {
192 while(!stop)
193 {
194 this.buf = new byte[512];
195
196 //讀取輸入的數據(阻塞讀)
197 try {
198 this.mInputStream.read(buf);
199 } catch (IOException e1) {
200 // TODO Auto-generated catch block
201 e1.printStackTrace();
202 }
203
204 //字符編碼轉換
205 try {
206 this.str = new String(this.buf, "GB2312").trim();
207 } catch (UnsupportedEncodingException e) {
208 // TODO Auto-generated catch block
209 e.printStackTrace();
210 }
211
212 Message msg = new Message();
213 msg.what = 1;
214 msg.obj = this.str;
215 //發送消息
216 mHandler.sendMessage(msg);
217
218 }
219 }
220 }
221
222
223 @Override
224 public void onDestroy()
225 {
226 super.onDestroy();
227
228 if(mReceiveThread != null)
229 {
230 stop = true;
231 mReceiveThread.interrupt();
232 }
233 }
234
235
236 }
兩個工程都修改好了，同樣，在模擬器上運行客戶端：
在真機上運行服務器端：
接着，點擊客戶端的“連接”按鈕，看到“連接成功”提示后輸入一些內容再點擊“發送”按鈕，此時客戶端顯示：
服務器端顯示：
接下來兩邊都可以隨意發送數據了。