Netbeans 空屏幕

Question

我在使用 netbeans gui 时遇到问题我之前制作过其他 gui，但最近我在通过按钮打开新的 window 时遇到了问题，我通常这样做只会打开一个空的灰色屏幕。请记住标记为主要作品的第一个表格，但是当我单击应该打开下一个 window 的按钮时，我只得到一个灰色的空白屏幕。

package wecare;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
 *
 * @author dnnmc
 */
public class Main extends javax.swing.JFrame {

    /**
     * Creates new form Main
     */
    File Reg= new File("Users.txt");
    public Main() {
        initComponents();
    }

    void ReadFile()
    {

            try {
                FileReader fr= new FileReader(Reg+"Users.txt");
            } catch (FileNotFoundException ex) {
                Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
            }
            System.out.println("File exist");


    }
    /**
     * 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() {

        jLabel1 = new javax.swing.JLabel();
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenu2 = new javax.swing.JMenu();
        jPanel1 = new javax.swing.JPanel();
        jPanel2 = new javax.swing.JPanel();
        SgnBtn = new javax.swing.JButton();
        jLabel4 = new javax.swing.JLabel();
        jPanel3 = new javax.swing.JPanel();
        Unametxt = new javax.swing.JTextField();
        PwordTxt = new javax.swing.JTextField();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        LogBtn = new javax.swing.JButton();
        jLabel5 = new javax.swing.JLabel();

        jLabel1.setText("jLabel1");

        jMenu1.setText("File");
        jMenuBar1.add(jMenu1);

        jMenu2.setText("Edit");
        jMenuBar1.add(jMenu2);

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setLayout(null);

        jPanel2.setBackground(new java.awt.Color(102, 255, 255));

        SgnBtn.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        SgnBtn.setText("Sign Up");
        SgnBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                SgnBtnActionPerformed(evt);
            }
        });

        jLabel4.setFont(new java.awt.Font("Agency FB", 0, 24)); // NOI18N
        jLabel4.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel4.setText("WeCare");

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGap(70, 70, 70)
                        .addComponent(SgnBtn, javax.swing.GroupLayout.PREFERRED_SIZE, 92, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGap(59, 59, 59)
                        .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 94, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(78, Short.MAX_VALUE))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup()
                .addGap(162, 162, 162)
                .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 170, Short.MAX_VALUE)
                .addComponent(SgnBtn)
                .addGap(110, 110, 110))
        );

        jPanel1.add(jPanel2);
        jPanel2.setBounds(0, 0, 240, 530);

        jPanel3.setBackground(new java.awt.Color(255, 255, 255));

        jLabel2.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel2.setText("User Name");

        jLabel3.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel3.setText("Password");

        LogBtn.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        LogBtn.setText("Login");

        jLabel5.setIcon(new javax.swing.ImageIcon(getClass().getResource("/wecare/rsz_1rsz_man.png"))); // NOI18N
        jLabel5.setText("jLabel5");

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel3Layout.createSequentialGroup()
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addGap(37, 37, 37)
                        .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel3)
                            .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                .addComponent(Unametxt, javax.swing.GroupLayout.DEFAULT_SIZE, 164, Short.MAX_VALUE)
                                .addComponent(PwordTxt))))
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addGap(88, 88, 88)
                        .addComponent(LogBtn))
                    .addGroup(jPanel3Layout.createSequentialGroup()
                        .addGap(68, 68, 68)
                        .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, 97, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(59, Short.MAX_VALUE))
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel3Layout.createSequentialGroup()
                .addGap(53, 53, 53)
                .addComponent(jLabel5)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 33, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(Unametxt, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(31, 31, 31)
                .addComponent(jLabel3)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(PwordTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(49, 49, 49)
                .addComponent(LogBtn)
                .addContainerGap(115, Short.MAX_VALUE))
        );

        jPanel1.add(jPanel3);
        jPanel3.setBounds(240, 0, 260, 530);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, 502, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, 533, Short.MAX_VALUE)
        );

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

    private void SgnBtnActionPerformed(java.awt.event.ActionEvent evt) {                                       
        // TODO add your handling code here:
        SignUp  sg= new SignUp (Reg);
        sg.setVisible(true);
    }                                      

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* 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(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Main.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() {
                new Main().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton LogBtn;
    private javax.swing.JTextField PwordTxt;
    private javax.swing.JButton SgnBtn;
    private javax.swing.JTextField Unametxt;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    // End of variables declaration                   
}

    package wecare;
import java.io.*;
import java.lang.Exception;
import java.io.File;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JOptionPane;
/**
 *
 * @author dnnmc
 */


public class SignUp extends javax.swing.JFrame {
  private File reg;
    /**
     * Creates new form SignUp
     */



    public SignUp() {
        initComponents();
    }

public SignUp(File Reg)
{
    reg=Reg;
}
    /**
     * 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() {

        jPanel3 = new javax.swing.JPanel();
        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jPanel4 = new javax.swing.JPanel();
        jLabel2 = new javax.swing.JLabel();
        UsnameTxt = new javax.swing.JTextField();
        jLabel3 = new javax.swing.JLabel();
        CPwrdTxt = new javax.swing.JTextField();
        jLabel4 = new javax.swing.JLabel();
        PwrdTxt1 = new javax.swing.JTextField();
        CrteBtn = new javax.swing.JButton();
        jLabel5 = new javax.swing.JLabel();
        EmailTxt = new javax.swing.JTextField();

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 100, Short.MAX_VALUE)
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 100, Short.MAX_VALUE)
        );

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setBackground(new java.awt.Color(0, 255, 255));

        jLabel1.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel1.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel1.setText("Sign Up");

        jPanel4.setBackground(new java.awt.Color(255, 255, 255));

        jLabel2.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel2.setText("Username");

        jLabel3.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel3.setText("Password");

        jLabel4.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel4.setText("Confirm Password");

        CrteBtn.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        CrteBtn.setText("Create");
        CrteBtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                CrteBtnActionPerformed(evt);
            }
        });

        jLabel5.setFont(new java.awt.Font("Onyx", 0, 24)); // NOI18N
        jLabel5.setText("Email");

        javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4);
        jPanel4.setLayout(jPanel4Layout);
        jPanel4Layout.setHorizontalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel4Layout.createSequentialGroup()
                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel4Layout.createSequentialGroup()
                        .addGap(48, 48, 48)
                        .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel5)
                            .addComponent(jLabel4)
                            .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                                .addComponent(PwrdTxt1, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGroup(jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE)
                                    .addComponent(UsnameTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
                                    .addComponent(jLabel3))
                                .addComponent(CPwrdTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addComponent(EmailTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE))))
                    .addGroup(jPanel4Layout.createSequentialGroup()
                        .addGap(149, 149, 149)
                        .addComponent(CrteBtn)))
                .addContainerGap(64, Short.MAX_VALUE))
        );
        jPanel4Layout.setVerticalGroup(
            jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel4Layout.createSequentialGroup()
                .addGap(25, 25, 25)
                .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(UsnameTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 33, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel3)
                .addGap(1, 1, 1)
                .addComponent(PwrdTxt1, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jLabel4)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(CPwrdTxt, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jLabel5)
                .addGap(12, 12, 12)
                .addComponent(EmailTxt, javax.swing.GroupLayout.DEFAULT_SIZE, 32, Short.MAX_VALUE)
                .addGap(18, 18, 18)
                .addComponent(CrteBtn)
                .addContainerGap())
        );

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(197, 197, 197)
                        .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 70, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(41, 41, 41)
                        .addComponent(jPanel4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(55, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(22, 22, 22)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 49, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jPanel4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(56, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

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

    private void CrteBtnActionPerformed(java.awt.event.ActionEvent evt) {                                        
        String pwd;
        String pwd1;

        try {
            // TODO add your handling code here:
             FileWriter fw = new FileWriter("User.txt");
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(UsnameTxt.getText());
            bw.newLine();
            pwd=PwrdTxt1.getText();
            pwd1=CPwrdTxt.getText();
            if (pwd.equals(pwd1))
            {
                bw.write(PwrdTxt1.getText());
            }
            else {
            JOptionPane.showMessageDialog(this, "Password dont Match");
            }
            fw.close();
        }  catch (IOException e) {
            e.printStackTrace();
    }

    }                                       

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* 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(SignUp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(SignUp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(SignUp.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(SignUp.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() {
                new SignUp().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JTextField CPwrdTxt;
    private javax.swing.JButton CrteBtn;
    private javax.swing.JTextField EmailTxt;
    private javax.swing.JTextField PwrdTxt1;
    private javax.swing.JTextField UsnameTxt;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JPanel jPanel4;
    // End of variables declaration                   

}

Answer 1

采用 File 参数的 SignUp 构造函数，Reg（应重命名 reg 以符合 Java 命名约定）从未出现调用 initComponents() 方法创建在显示之前需要添加到 GUI 的组件。如果不调用它，我希望 window 应该保持为空。要修复：在 class 的构造函数中调用此方法。

这可以通过在第二个构造函数中调用 this() 来完成，以便首先调用无参数默认构造函数：

public SignUp(File reg) { // reg should not be capitalized
    this(); // first call the no-arg default constructor.
    this.reg = reg;
}

或者直接调用方法解决：

public SignUp(File reg) {
    initComponents(); // put gui elements into the window
    this.reg = reg;
}

第一种方法对我来说似乎更简洁，因为如果您决定向 class 的构造函数添加更多功能，您只需执行一次，避免运行与 "DRY"规则。

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