Java GUI构造函数被调用两次致双窗口弹出问题求助

问题根源 #

• Servidor是继承自RummyClient的静态内部类，当你在main方法中创建Servidor实例时，会触发父类RummyClient的成员初始化，执行public GUI gui = new GUI();，生成第一个窗口。
• 紧接着你又创建了RummyClient的实例并启动线程，这会再次执行public GUI gui = new GUI();，生成第二个窗口。

解决方案 #

方案一：将GUI实例改为静态单例

把RummyClient中的gui成员改为静态，确保全局只初始化一次：

public class RummyClient implements Runnable{
    // 改为静态单例，仅初始化一次
    public static GUI gui = new GUI();
    public static Servidor servidor;

    // 后续代码保持不变...
}

方案二：让Servidor不再继承RummyClient

调整Servidor的结构，避免不必要的继承关系：

public class RummyClient implements Runnable{
    public GUI gui = new GUI();
    public static Servidor servidor;

    public static void main(String[] args) throws UnknownHostException, IOException {
        RummyClient client = new RummyClient();
        servidor = new Servidor(25565, "localhost", client);
        new Thread(client).start();
    }
    
    @Override
    public void run() {
        while(true) {
            gui.repaint();
        }
    }
    
    // GUI类代码保持不变...
    
    // 修改Servidor，不再继承RummyClient
    static class Servidor {
        Socket s;
        PrintWriter out;
        Scanner in;
        private RummyClient client;

        public Servidor(int port, String ip, RummyClient client) throws UnknownHostException, IOException {
            this.client = client;
            this.s = new Socket(ip, port);
            this.out = new PrintWriter(s.getOutputStream());
            this.in = new Scanner(s.getInputStream());
            Thread input = new Thread(new Input());
            input.start();
        }

        public void send(String text) {
            out.println(text);
            out.flush();
        }

        class Input implements Runnable {
            @Override
            public void run() {
                while(true) {
                    String incoming = in.nextLine();
                    switch (incoming) {
                        case "ready":
                            client.gui.start();
                            break;
                    }
                }
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者user21102712