在Android Socket编程中，服务器端给出错误：

我试图为一个项目实现一个Android Socket编程程序，但代码似乎给出了两个错误。尽我所能解决这些问题，但我们将非常感谢您的帮助，谢谢。代码如下所示，错误“公共类型服务器必须在其自己的文件中定义”和“R不能解析为变量”以粗体显示：

package com.example.androidsocketserver;



import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.widget.TextView;
**public class Server extends Activity** {

    private ServerSocket serverSocket;

    Handler updateConversationHandler;

    Thread serverThread = null;

    private TextView text;

    public static final int SERVERPORT = 6000;

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        **setContentView(R.layout.main);**

        **text = (TextView) findViewById(R.id.text2);**

        updateConversationHandler = new Handler();

        this.serverThread = new Thread(new ServerThread());
        this.serverThread.start();

    }

    @Override
    protected void onStop() {
        super.onStop();
        try {
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    class ServerThread implements Runnable {

        public void run() {
            Socket socket = null;
            try {
                serverSocket = new ServerSocket(SERVERPORT);
            } catch (IOException e) {
                e.printStackTrace();
            }
            while (!Thread.currentThread().isInterrupted()) {

                try {

                    socket = serverSocket.accept();

                    CommunicationThread commThread = new CommunicationThread(socket);
                    new Thread(commThread).start();

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    class CommunicationThread implements Runnable {

        private Socket clientSocket;

        private BufferedReader input;

        public CommunicationThread(Socket clientSocket) {

            this.clientSocket = clientSocket;

            try {

                this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));

            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        public void run() {

            while (!Thread.currentThread().isInterrupted()) {

                try {

                    String read = input.readLine();

                    updateConversationHandler.post(new updateUIThread(read));

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

    class updateUIThread implements Runnable {
        private String msg;

        public updateUIThread(String str) {
            this.msg = str;
        }

        @Override
        public void run() {
            text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
        }
    }
}

---

服务器是文件中唯一的公共类。如果在同一文件中定义了其他活动，则需要创建新的文件调用服务器，并将服务器活动放入该文件。

谢谢。将MainActivity.java文件更改为Server.java，它就工作了。您能告诉我如何修复“R不能解析为变量”错误吗？请尝试清理您的项目。如果错误仍然存在，请检查xml文件以查看是否存在任何错误