package com.example.ksswj; import androidx.appcompat.app.AppCompatActivity; import android.annotation.SuppressLint; import android.os.Bundle; import android.os.Handler; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.Socket; import java.net.UnknownHostException; public class MainActivity extends AppCompatActivity { private EditText ipEditText; private EditText portEditText; private TextView messageTextView; private BufferedReader in; private Socket socket; private Handler handler = new Handler(); @SuppressLint("MissingInflatedId") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ipEditText = findViewById(R.id.ipEditText); portEditText = findViewById(R.id.portEditText); messageTextView = findViewById(R.id.messageTextView); Button connectButton = findViewById(R.id.connectButton); connectButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String ip = ipEditText.getText().toString(); int port = Integer.parseInt(portEditText.getText().toString()); new Thread(new Runnable() { @Override public void run() { try { socket = new Socket(ip, port); in = new BufferedReader(new InputStreamReader(socket.getInputStream())); // 在主页面中的窗口中实时显示消息 while (true) { String message = in.readLine(); if (message == null) { break; } handler.post(new Runnable() { @Override public void run() { messageTextView.append(message + "\n"); } }); } } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }).start(); } }); } @Override protected void onDestroy() { super.onDestroy(); try { if (in != null) { in.close(); } if (socket != null) { socket.close(); } } catch (IOException e) { e.printStackTrace(); } } }我还需要在上面代码中加入一个对话框，能够向端口发送消息，能帮我加上代码吗

当然可以，你需要在 layout 文件夹下创建一个新的 xml 文件作为对话框的布局，比如命名为 dialog_send_message.xml。然后在 MainActivity 中添加一个方法，用来弹出对话框并向端口发送消息。代码如下：

package com.example.ksswj;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class MainActivity extends AppCompatActivity {

    private EditText ipEditText;
    private EditText portEditText;
    private TextView messageTextView;
    private BufferedReader in;
    private PrintWriter out;
    private Socket socket;
    private Handler handler = new Handler();

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

        ipEditText = findViewById(R.id.ipEditText);
        portEditText = findViewById(R.id.portEditText);
        messageTextView = findViewById(R.id.messageTextView);

        Button connectButton = findViewById(R.id.connectButton);
        connectButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String ip = ipEditText.getText().toString();
                int port = Integer.parseInt(portEditText.getText().toString());
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            socket = new Socket(ip, port);
                            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                            out = new PrintWriter(socket.getOutputStream(), true);
                            // 在主页面中的窗口中实时显示消息
                            while (true) {
                                String message = in.readLine();
                                if (message == null) {
                                    break;
                                }
                                handler.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        messageTextView.append(message + "\n");
                                    }
                                });
                            }
                        } catch (UnknownHostException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }).start();
            }
        });

        Button sendMessageButton = findViewById(R.id.sendMessageButton);
        sendMessageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showSendMessageDialog();
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        try {
            if (in != null) {
                in.close();
            }
            if (out != null) {
                out.close();
            }
            if (socket != null) {
                socket.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void showSendMessageDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        LayoutInflater inflater = getLayoutInflater();
        View view = inflater.inflate(R.layout.dialog_send_message, null);
        final EditText messageEditText = view.findViewById(R.id.messageEditText);
        builder.setView(view)
                .setTitle("发送消息")
                .setPositiveButton("发送", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        String message = messageEditText.getText().toString();
                        if (out != null) {
                            out.println(message);
                        }
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                })
                .create()
                .show();
    }
}

其中，`showSendMessageDialog()` 方法用来弹出对话框，`dialog_send_message.xml` 文件作为对话框的布局文件。在对话框中，用户可以输入要发送的消息，然后点击“发送”按钮将消息发送到端口上。