Android基于socket实现的简单C/S聊天通信功能

实现Android基于socket的C/S聊天通信功能，可以分成如下几个步骤：

1. 建立Server端

• 使用Java的ServerSocket类创建Server端。
• 在Server端运行一个死循环，等待Client发来连接请求（使用Socket类进行连接）。
• 接收Client发送的消息，处理并返回数据给Client。

下面是一个Java Server端的示例代码：

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(7777);
        System.out.println("Server started.");

        // 等待客户端连接
        Socket clientSocket = serverSocket.accept();
        System.out.println("Server connected to Client: " + clientSocket.getInetAddress());

        // 读取客户端发来的消息
        InputStream inputStream = clientSocket.getInputStream();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

        String line = "";
        while ((line = bufferedReader.readLine()) != null) {
            System.out.println("Client says: " + line);
        }

        // 写入数据到客户端
        OutputStream outputStream = clientSocket.getOutputStream();
        PrintWriter out = new PrintWriter(new OutputStreamWriter(outputStream));
        out.println("Hello Client!");
        out.flush();

        clientSocket.close();
        serverSocket.close();
    }
}

2. 建立Client端

• 使用Java的Socket类创建Client端。
• 连接到Server端。
• 发送消息到Server端，等待Server端返回的消息。

下面是一个Java Client端的示例代码：

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 7777);
        System.out.println("Client connected to Server.");

        // 向Server发送消息
        OutputStream outputStream = socket.getOutputStream();
        PrintWriter out = new PrintWriter(new OutputStreamWriter(outputStream));
        out.println("Hello Server!");
        out.flush();

        // 读取Server返回的消息
        InputStream inputStream = socket.getInputStream();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

        String line = "";
        while ((line = bufferedReader.readLine()) != null) {
            System.out.println("Server says: " + line);
        }

        socket.close();
    }
}

3. Android端的实现

• 在Android项目中添加AndroidManifest.xml文件中添加网络权限 <uses-permission android:name="android.permission.INTERNET"/>。
• 使用Android的线程池处理Server端向Client传递数据的任务。
• 通过Socket连接到Server端。
• 使用BufferedReader和PrintWriter进行数据读写操作。

下面是一个Android端的实现示例代码：

public class MainActivity extends AppCompatActivity {
    private EditText mEditText;
    private Button mButton;
    private TextView mTextView;
    private ExecutorService mThreadPool;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mEditText = findViewById(R.id.et_text);
        mButton = findViewById(R.id.btn_send);
        mTextView = findViewById(R.id.tv_text);
        mThreadPool = Executors.newCachedThreadPool();

        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String text = mEditText.getText().toString().trim();
                mThreadPool.execute(new ServerTask(text));
                mEditText.setText("");
            }
        });
    }

    private class ServerTask implements Runnable {
        private String mMessage;

        public ServerTask(String message) {
            mMessage = message;
        }

        @Override
        public void run() {
            try {
                Socket socket = new Socket("localhost", 7777);
                PrintWriter writer = new PrintWriter(socket.getOutputStream());
                BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                writer.println(mMessage);
                writer.flush();
                String result = reader.readLine();
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        mTextView.setText(result);
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}