java - Swing 表单无法正确显示

Question

我正在尝试使用基本的 GUI 生成 UDP 服务器。我遇到的问题是，当我将 Datagram 套接字从 main 方法移动到它自己的方法时，以便我可以输出到 jTextArea 我的 GUI 停止显示。我相信它与 setVisible(true) 有关，但无论我做什么，我似乎都无法让它正确显示，任何帮助将不胜感激

package Assignment1;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class UDPServer extends javax.swing.JFrame {

    public UDPServer() throws IOException {
        initComponents();
        setVisible(true);
        FileRead();
        runServer();
    }


    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        ClearLog = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        TextArea = new javax.swing.JTextArea();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        ClearLog.setText("Clear Log");
        ClearLog.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ClearLogActionPerformed(evt);
            }
        });

        TextArea.setColumns(20);
        TextArea.setRows(5);
        jScrollPane1.setViewportView(TextArea);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
            .addComponent(ClearLog, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(ClearLog)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 271, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void ClearLogActionPerformed(java.awt.event.ActionEvent evt) {                                         
        TextArea.setText("");
    }                                        

    public static void main(String args[]) throws IOException {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
      /*  try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(UDPServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(UDPServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(UDPServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(UDPServer.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
       java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    new UDPServer().setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(UDPServer.class.getName()).log(Level.SEVERE, null, ex);
                }


            }
        }

        );   
    }



    public void FileRead() throws IOException {

        String file_name = "C:/Users/Ross/Documents/NetBeansProjects/Assignment1/src/Assignment1/Data.txt";

        try {
            ReadFile file = new ReadFile(file_name);
            String[] aryLines = file.OpenFile();

            int i;
            for (i=0; i < aryLines.length; i++) {
                System.out.println(aryLines[i]);
            }
        }
        catch (IOException e) {
            System.out.println( e.getMessage());
        }
    }

     public void runServer(){

         try(DatagramSocket aSocket = new DatagramSocket(8789)) {

            byte[] buffer = new byte[1000];

                DatagramPacket request = new DatagramPacket(buffer, buffer.length);

                        while(true)
                            {
                aSocket.receive(request);
                TextArea.setText("Client Request: " + new String(request.getData(), 0, request.getLength()));
                                DatagramPacket reply = new DatagramPacket(request.getData(), request.getLength(), 
                    request.getAddress(), request.getPort());
                                aSocket.send(reply);
                            }
        }catch (SocketException e){System.out.println("Socket: " + e.getMessage());
        }catch (IOException e) {System.out.println("IO: " + e.getMessage());
        } 
     }

      public void SetText(){

        TextArea.setText("Hello");
        TextArea.append("This is a test"); 

     }

    // Variables declaration - do not modify                     
    private javax.swing.JButton ClearLog;
    private javax.swing.JTextArea TextArea;
    private javax.swing.JScrollPane jScrollPane1;
    // End of variables declaration                   
}

Answer 1

发生这种情况是因为您正在调用 The Event Dispatch Thread 上的 runServer 方法。 。如果 runServer 方法阻塞，那么您的用户界面将不会更新。

一个快速解决方案是按如下方式更新构造函数，以便 runServer 在其自己的线程中运行。

public UDPServer() throws IOException {
    initComponents();
    setVisible(true);
    FileRead();
    new Thread(()->runServer()).start();
}

但是您应该在 EDT 中进行任何 UI 更新。例如，TextArea.setTex 应在 EDT 中完成。您可以在上面链接的文档中查看如何完成此操作。