java - 需要一点帮助，隐藏/禁用jbutton

我正在研究学生/管理员门户应用程序，并且需要一些帮助来隐藏/启用jbutton。

如果用户以管理员身份登录，则应该启用/显示jbutton。

如果用户以学生身份登录，则应该禁用/消失jbutton。

例如，我在Jframe1中有按钮1，并将在JFrame2中隐藏该按钮。
请找到下面的代码-带有双星号的代码是我的代码，用于将frame2中jbutton的可见性设置为隐藏。我还将jbutton的变量修饰符设置为public。

表格1-登录

package testlogin;
import java.sql.*;
import javax.swing.JOptionPane;

////////////////////////////////
public class login extends javax.swing.JFrame {
public welc welc;
public Statement st;
public int xtry =1,ytry=4,trig;
Connection conn=null;
PreparedStatement pst =null;
ResultSet rs =null;


 ///
    public login() {

        initComponents();
         conn=mysqlconnect.Connectdb();    //class connection
    }

//////////

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        user1 = new javax.swing.JTextField();
        submitbtn = new javax.swing.JButton();
        pass1 = new javax.swing.JPasswordField();
        jPanel2 = new javax.swing.JPanel();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jLabel4 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setCursor(new java.awt.Cursor(java.awt.Cursor.DEFAULT_CURSOR));
        setMaximumSize(new java.awt.Dimension(350, 300));
        setMinimumSize(new java.awt.Dimension(350, 100));
        setName("Login"); // NOI18N
        setPreferredSize(new java.awt.Dimension(350, 230));
        setResizable(false);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowOpened(java.awt.event.WindowEvent evt) {
                formWindowOpened(evt);
            }
        });

        jLabel1.setText("LOGIN");

        jLabel2.setText("STUDENT NUMBER:");

        jLabel3.setText("PASSWORD:");

        submitbtn.setText("SUBMIT");
        submitbtn.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                submitbtnActionPerformed(evt);
            }
        });

        pass1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                pass1MouseClicked(evt);
            }
        });
        pass1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                pass1ActionPerformed(evt);
            }
        });

        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(19, 19, 19)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(84, 84, 84)
                                .addComponent(jLabel1))
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addComponent(jLabel3)
                                    .addComponent(jLabel2))
                                .addGap(36, 36, 36)
                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                    .addComponent(user1)
                                    .addComponent(pass1, javax.swing.GroupLayout.PREFERRED_SIZE, 137, javax.swing.GroupLayout.PREFERRED_SIZE)))))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(88, 88, 88)
                        .addComponent(submitbtn, javax.swing.GroupLayout.PREFERRED_SIZE, 103, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(185, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addComponent(jLabel1)
                .addGap(41, 41, 41)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(user1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(18, 18, 18)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3)
                    .addComponent(pass1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(41, 41, 41)
                .addComponent(submitbtn)
                .addContainerGap())
        );

        jButton1.setText("LOGIN AS ADMIN");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jButton2.setText("LOGIN AS STUDENT");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jLabel4.setText("LOGIN");

        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()
                        .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 137, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(30, 30, 30)
                        .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 147, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGap(138, 138, 138)
                        .addComponent(jLabel4)))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup()
                .addGap(26, 26, 26)
                .addComponent(jLabel4)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 48, Short.MAX_VALUE)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jButton2))
                .addGap(84, 84, 84))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(0, 70, Short.MAX_VALUE)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(23, 23, 23))
        );

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

    private void submitbtnActionPerformed(java.awt.event.ActionEvent evt) {

            String sql = "select *from tablelogin where username = ? and password = ?";      //check Password and Username
         try{
             pst = conn.prepareStatement(sql);
             pst.setString(1,user1.getText());      //gets user text from textbox
             pst.setString(2,pass1.getText());       //gets pass text from textbox
             rs = pst.executeQuery();               //send to query

        if (rs.next()){                            //query will test if username & password == user1 & user2
            if (trig==1){                  //triggers the condition if user or admin
            JOptionPane.showMessageDialog(null, "YOU ARE LOGGED IN AS AN ADMIN!");
            welc spark = new welc();
        spark.btn_create.setVisible(false);

            }
            else{
            JOptionPane.showMessageDialog(null, "YOU ARE LOGGED IN AS A STUDENT!");

            }
            JOptionPane.showMessageDialog(null, "Connection Established!");

             this.dispose();
             new welc().setVisible(true);
                }
        else
                if (xtry<=4){                       //condition for number of tries
                    JOptionPane.showMessageDialog(null, "INVALID USERNAME OR PASSWORD!\n(Only "+ytry+" tries left)");
                    xtry++;                     //increment & decrement for tries
                    ytry--;
                }
                else {                          //dialog exit
                    JOptionPane.showMessageDialog(null, "Maximum number of tries exceeded. Program will exit..");
                    System.exit(0);
                }
                    }
       catch(Exception e){

        }




    }

    private void pass1ActionPerformed(java.awt.event.ActionEvent evt) {

    }

    private void pass1MouseClicked(java.awt.event.MouseEvent evt) {
        pass1.setText("");
    }

    private void formWindowOpened(java.awt.event.WindowEvent evt) {
       jPanel1.hide();
    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
       jPanel1.show();                                      //show panel1
       jPanel2.hide();                                      // hide panel2
       jLabel2.setText("USERNAME:");                        //set text to username
       trig=1;

    }

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
         jPanel1.show();
       jPanel2.hide();




    }


    public static void main(String args[]) {


        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new login().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPasswordField pass1;
    public javax.swing.JButton submitbtn;
    private javax.swing.JTextField user1;
    // End of variables declaration
}

框架2-Welc

package testlogin;

import java.awt.Color;                  //import for colors
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.concurrent.ExecutionException;
import javax.swing.JOptionPane;
import net.proteanit.sql.DbUtils;       //import for dbutils/table


public class welc extends javax.swing.JFrame {
public String username2;
Connection conn=null;
PreparedStatement pst =null;
ResultSet rs =null;




////////////

    public welc() {
        Color color = new Color(0,153,51);  //bgcolor
        getContentPane().setBackground(color);
        conn=mysqlconnect.Connectdb();    //class connection
        initComponents();

    }



    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel8 = new javax.swing.JLabel();
        jComboBox1 = new javax.swing.JComboBox();
        btn_create = new javax.swing.JButton();
        btn_create1 = new javax.swing.JButton();
        jLabel1 = new javax.swing.JLabel();
        btn_reglist = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setBackground(new java.awt.Color(0, 153, 51));
        setMaximumSize(new java.awt.Dimension(1000, 600));
        setMinimumSize(new java.awt.Dimension(500, 500));
        setPreferredSize(new java.awt.Dimension(1000, 600));
        setResizable(false);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowOpened(java.awt.event.WindowEvent evt) {
                formWindowOpened(evt);
            }
        });

        jPanel1.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));
        jPanel1.setMinimumSize(new java.awt.Dimension(875, 400));
        jPanel1.setPreferredSize(new java.awt.Dimension(875, 400));

        jLabel8.setFont(new java.awt.Font("Tahoma", 1, 18)); // NOI18N
        jLabel8.setText("PERSONAL INFORMATION");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel8)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel8)
                .addContainerGap(374, Short.MAX_VALUE))
        );

        jComboBox1.setEditable(true);
        jComboBox1.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "HOME", "ACCOUNT", "SCHEDULE", "LOGOUT" }));
        jComboBox1.setFocusable(false);
        jComboBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1ActionPerformed(evt);
            }
        });

        btn_create.setText("CREATE AN ACCOUNT");
        btn_create.setEnabled(false);
        btn_create.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btn_createActionPerformed(evt);
            }
        });

        btn_create1.setText("REMOVE AN ACCOUNT");
        btn_create1.setEnabled(false);

        btn_reglist.setText("CHECK RECORDS");
        btn_reglist.setEnabled(false);
        btn_reglist.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btn_reglistActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(75, 75, 75)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 840, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addGap(426, 426, 426)
                                .addComponent(jLabel1))
                            .addGroup(layout.createSequentialGroup()
                                .addGap(41, 41, 41)
                                .addComponent(btn_reglist)
                                .addGap(37, 37, 37)
                                .addComponent(btn_create)
                                .addGap(18, 18, 18)
                                .addComponent(btn_create1)))))
                .addContainerGap(110, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(59, 59, 59)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(btn_create)
                    .addComponent(btn_create1)
                    .addComponent(jLabel1)
                    .addComponent(btn_reglist))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 409, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(100, Short.MAX_VALUE))
        );

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

    private void formWindowOpened(java.awt.event.WindowEvent evt) {


    }

    private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
    }

    private void btn_createActionPerformed(java.awt.event.ActionEvent evt) {
        new create().show();
        this.hide();
    }

    private void btn_reglistActionPerformed(java.awt.event.ActionEvent evt) {
            new checkreg().show();
            this.hide();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {



        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new welc().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    public javax.swing.JButton btn_create;
    public static javax.swing.JButton btn_create1;
    public javax.swing.JButton btn_reglist;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel8;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration

    private void setOpaque(boolean b) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }
}

最佳答案

更改组件的可见性或添加或删除组件后，您将需要在组件的容器(我相信您的示例中至少是第二个窗口中的contentPane)上调用revalidate()和repaint() -布置其组件，然后重新绘制自身以摆脱其窗口上的脏区。

btn_create.setVisible(false);
getContentPane().revalidate();
getContentPane().repaint();

话虽如此，您可以通过不翻转用户窗口，而仅使用一个JFrame并通过CardLayout交换JPanel视图来极大地改善代码。

编辑
这是您的错误:

welc spark = new welc();
spark.btn_create.setVisible(false);

您正在创建一个全新的Welc对象，称为spark，一个从不显示，然后设置其组件之一的属性，该组件的对于该welc对象起作用，但这不会对显示的welc对象产生影响，因为它们是两个完全不同的对象。解决方案是为Welc(应重命名为Welc)提供一个公共方法，该方法允许您更改其按钮的状态，然后在显示的Welc对象上调用此方法，而不是在Web对象上创建的新的和不同的Welc对象。点。

例如。，

// capitalize class name
public class Login extends javax.swing.JFrame {
   // create one instance only of Welc:
   public Welc welc = new Welc();  //!! added

   // ....


   private void submitbtnActionPerformed(java.awt.event.ActionEvent evt) {

      // .... code deleted for simplicfication

            if (trig == 1) {
               JOptionPane.showMessageDialog(null,
                     "YOU ARE LOGGED IN AS AN ADMIN!");
               // !! Welc spark = new Welc(); // removed
               // spark.btn_create.setVisible(false);
               welc.btnCreateSetVisible(false); //!! add this
            } else {
               JOptionPane.showMessageDialog(null,
                     "YOU ARE LOGGED IN AS A STUDENT!");
            }
            JOptionPane.showMessageDialog(null, "Connection Established!");
            this.dispose();
            //!! new Welc().setVisible(true);
            welc.setVisible(true);
         }
      } catch (Exception e) {
         //!! never have empty catch blocks
      }
   }


   private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
      //!! never use deprecated methods
      jPanel1.show();
      jPanel2.hide();
      jLabel2.setText("USERNAME:");
      trig = 1;
   }

// ....

编辑2

进一步建议:

在进一步审查中，我可以看到您想如何通过对话框窗口进行登录，但是我只想使用模式对话框(例如JDialog或JOptionPane)来进行登录。即使尚未显示主JFrame，也可以将其用作“调用”窗口。

我建议您不要让登录窗口直接修改主GUI窗口，因为这会不必要地增加类的耦合。

而是考虑为您的登录类型创建一个枚举，说一个叫做LoginType的东西，并给它所有必需的元素，例如STUDENT和ADMINISTRATOR。

然后，您可以为主GUI提供一个方法public void setLoginType(LoginType loginType)，在该方法中，让主GUI根据登录类型对自身进行所有操作。

将数据库代码与GUI代码分开。

确保在自己的线程中执行数据库代码，该线程不在Swing事件线程中。

编辑3
例如:

import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Insets;
import javax.swing.*;
public class MyLogin {
   private static void createAndShowGUI() {
      MainGui mainGui = new MainGui();

      JFrame mainFrame = new JFrame("Main GUI");
      mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      mainFrame.add(mainGui);
      mainFrame.pack();
      mainFrame.setLocationRelativeTo(null);

      LoginDialogPanel dialogPanel = new LoginDialogPanel();

      LoginType loginType = null;

      while (loginType == null) {
         int result = JOptionPane.showConfirmDialog(mainFrame, dialogPanel, "Login",
                     JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);

         if (result != JOptionPane.OK_OPTION) {
            // JOptionPane to make sure they want to exit
            // exit
            return;
         }

         loginType = dialogPanel.getLoginType();

      }

      System.out.println(loginType.getName());

      // TODO: check login credentials via database in background thread
      // I'd use a SwingWorker and add a PropertyChangeListener to it.
      // In the prop chng listener, if the worker's state is SwingWorker.StateValue.DONE
      // I'd show the mainFrame GUI if the credentials are OK

      System.out.println("User name: " + dialogPanel.getUserName());
      System.out.print("Never do this, never change a password to String: ");

      // TODO: delete the line of code below
      System.out.println("Password: " + new String(dialogPanel.getPassword())); // ***** !!

      mainGui.setLoginType(loginType);
      mainGui.setUser(dialogPanel.getUserName());

      mainFrame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGUI();
         }
      });
   }
}

// parts of my main GUI

@SuppressWarnings("serial")
class MainGui extends JPanel {

   private LoginType loginType;
   private JButton showForAllTypesButton = new JButton("Show for all");
   private JButton showForAdminButton = new JButton("Show for admin");
   private JTextField userField = new JTextField(10);

   public MainGui() {
      userField.setEditable(false);
      userField.setFocusable(false);

      add(new JLabel("User:"));
      add(userField);
      add(Box.createHorizontalStrut(15));
      add(showForAllTypesButton);
      add(showForAdminButton);
   }

   public void setLoginType(LoginType loginType) {
      this.loginType = loginType;
      showForAdminButton.setVisible(loginType == LoginType.ADMINISTRATOR);
      revalidate();
      repaint();
   }

   public void setUser(String user) {
      userField.setText(user);
   }

   public LoginType getLoginType() {
      return loginType;
   }

}

// parts of my login dialog jpanel

class LoginDialogPanel extends JPanel {
   private static final String TITLE = "Login Type";
   private boolean loginSuccessful = false;

   private ButtonGroup loginTypeBtnGroup = new ButtonGroup();
   private JTextField userNameField = new JTextField(10);
   private JPasswordField passwordField = new JPasswordField(10);

   public LoginDialogPanel() {
      setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
      JLabel titleLabel = new JLabel(TITLE, SwingConstants.CENTER);
      titleLabel.setFont(titleLabel.getFont().deriveFont(Font.BOLD, 32));
      JPanel titlePanel = new JPanel();
      titlePanel.add(titleLabel);
      add(titlePanel);

      JPanel radioWrapperPanel = getLoginTypePanel();
      add(radioWrapperPanel);
      add(getNamePasswordPanel());
   }

   private JPanel getLoginTypePanel() {
      JPanel radioBtnPanel = new JPanel(new GridLayout(0, 1));
      for (LoginType loginType : LoginType.values()) {
         JRadioButton radioBtn = new JRadioButton(loginType.getName());
         radioBtn.setActionCommand(loginType.toString());
         loginTypeBtnGroup.add(radioBtn);
         radioBtnPanel.add(radioBtn);
      }
      JPanel radioWrapperPanel = new JPanel();
      radioWrapperPanel.add(radioBtnPanel);
      radioWrapperPanel.setBorder(BorderFactory.createTitledBorder("Login Type"));
      return radioWrapperPanel;
   }

   private JPanel getNamePasswordPanel() {
      JPanel namePasswordPanel = new JPanel(new GridBagLayout());
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.insets = new Insets(5, 5, 5, 5);
      gbc.gridx = 0;
      gbc.gridy = 0;
      gbc.anchor = GridBagConstraints.EAST;
      gbc.fill = GridBagConstraints.BOTH;
      gbc.weightx = 1.0;
      gbc.weighty = 1.0;
      namePasswordPanel.add(new JLabel("User Name:", SwingConstants.TRAILING), gbc);

      gbc.gridy = 1;
      namePasswordPanel.add(new JLabel("Password:", SwingConstants.TRAILING), gbc);

      gbc.gridx = 1;
      gbc.gridy = 0;
      gbc.fill = GridBagConstraints.HORIZONTAL;
      namePasswordPanel.add(userNameField, gbc);

      gbc.gridy = 1;
      namePasswordPanel.add(passwordField, gbc);

      JPanel namePasswordWrapperPanel = new JPanel();
      namePasswordWrapperPanel.add(namePasswordPanel);
      namePasswordPanel.setBorder(BorderFactory.createTitledBorder("Login Credentials"));
      return namePasswordPanel;
   }

   public boolean isLoginSuccessful() {
      return loginSuccessful;
   }

   public LoginType getLoginType() {
      ButtonModel model = loginTypeBtnGroup.getSelection();
      if (model == null) {
         return null; // nothing selected
      }

      return LoginType.valueOf(LoginType.class, model.getActionCommand());
   }

   public String getUserName() {
      return userNameField.getText();
   }

   public char[] getPassword() {
      return passwordField.getPassword();
   }

}

enum LoginType {
   STUDENT("Student"), ADMINISTRATOR("Administrator");
   private String name;

   private LoginType(String name) {
      this.name = name;
   }

   public String getName() {
      return name;
   }

}

关于java - 需要一点帮助，隐藏/禁用jbutton，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/25572243/