JFrame is not adding a JPanel to the frame

Question

I am attempting to code tick-tac toe just to improve my coding skills. In my previous projects, in order to create a new screen, I just created a new JFrame and set that as visible and the other one as not visible. However, this project, I have decided to use JPanels and remove the panelOne and add panelTwo . I have looked at previous StackOverflow questions on this subject, and have imported it into my code with a few modifications.

In my case, the code is removing panelOne but is not adding panelTwo . My code is below.

package Main;

import javax.swing.JFrame;

public class MainFrame extends JFrame {

public MainFrame() {
    initComponents();
}

void swapPanel(){
    new Thread(new Runnable(){
        @Override
        public void run() {
            MainFrame.this.remove(panelOne);
            MainFrame.this.add(panelTwo);
            MainFrame.this.invalidate();
            MainFrame.this.revalidate();
            MainFrame.this.pack(); 
        }

    }).start();
}

void singlePlayer(){
    swapPanel();
}

void multiPlayer(){
    swapPanel();
}

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

    panelTwo = new javax.swing.JPanel();
    firstVerticalLine = new javax.swing.JSeparator();
    secondVerticalLine = new javax.swing.JSeparator();
    firstRowLine1 = new javax.swing.JSeparator();
    secondRowLine1 = new javax.swing.JSeparator();
    firstRowLine2 = new javax.swing.JSeparator();
    secondRowLine2 = new javax.swing.JSeparator();
    firstRowLine3 = new javax.swing.JSeparator();
    secondRowLine3 = new javax.swing.JSeparator();
    jLabel1 = new javax.swing.JLabel();
    panelOne = new javax.swing.JPanel();
    singlePlayerButton = new javax.swing.JButton();
    mulitPlayerButton = new javax.swing.JButton();

    panelTwo.setMaximumSize(new java.awt.Dimension(409, 328));
    panelTwo.setMinimumSize(new java.awt.Dimension(409, 328));
    panelTwo.setPreferredSize(new java.awt.Dimension(409, 328));

    firstVerticalLine.setOrientation(javax.swing.SwingConstants.VERTICAL);

    secondVerticalLine.setOrientation(javax.swing.SwingConstants.VERTICAL);
    secondVerticalLine.setToolTipText("");

    firstRowLine1.setMinimumSize(new java.awt.Dimension(51, 10));
    firstRowLine1.setPreferredSize(new java.awt.Dimension(55, 10));

    javax.swing.GroupLayout panelTwoLayout = new javax.swing.GroupLayout(panelTwo);
    panelTwo.setLayout(panelTwoLayout);
    panelTwoLayout.setHorizontalGroup(
        panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(panelTwoLayout.createSequentialGroup()
            .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(firstRowLine1, javax.swing.GroupLayout.DEFAULT_SIZE, 118, Short.MAX_VALUE)
                .addComponent(secondRowLine1))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(firstVerticalLine, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(firstRowLine2, javax.swing.GroupLayout.DEFAULT_SIZE, 133, Short.MAX_VALUE)
                .addComponent(secondRowLine2))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(secondVerticalLine, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(firstRowLine3, javax.swing.GroupLayout.DEFAULT_SIZE, 130, Short.MAX_VALUE)
                .addComponent(secondRowLine3)))
    );
    panelTwoLayout.setVerticalGroup(
        panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(firstVerticalLine)
        .addComponent(secondVerticalLine)
        .addGroup(panelTwoLayout.createSequentialGroup()
            .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(panelTwoLayout.createSequentialGroup()
                    .addGap(104, 104, 104)
                    .addComponent(firstRowLine1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(102, 102, 102)
                    .addComponent(secondRowLine1, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(panelTwoLayout.createSequentialGroup()
                    .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(panelTwoLayout.createSequentialGroup()
                            .addGap(103, 103, 103)
                            .addComponent(firstRowLine2, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGroup(panelTwoLayout.createSequentialGroup()
                            .addGap(102, 102, 102)
                            .addComponent(firstRowLine3, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE)))
                    .addGap(102, 102, 102)
                    .addGroup(panelTwoLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(secondRowLine3, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(secondRowLine2, javax.swing.GroupLayout.PREFERRED_SIZE, 10, javax.swing.GroupLayout.PREFERRED_SIZE))))
            .addContainerGap(102, Short.MAX_VALUE))
    );

    jLabel1.setText("jLabel1");

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setTitle("Tic-Tac Toe");
    setMinimumSize(new java.awt.Dimension(409, 328));

    panelOne.setMinimumSize(new java.awt.Dimension(409, 328));

    singlePlayerButton.setText("Singleplayer");
    singlePlayerButton.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            singlePlayerButtonActionPerformed(evt);
        }
    });

    mulitPlayerButton.setText("Multiplayer");
    mulitPlayerButton.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            mulitPlayerButtonActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout panelOneLayout = new javax.swing.GroupLayout(panelOne);
    panelOne.setLayout(panelOneLayout);
    panelOneLayout.setHorizontalGroup(
        panelOneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(panelOneLayout.createSequentialGroup()
            .addGap(157, 157, 157)
            .addGroup(panelOneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(singlePlayerButton, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(mulitPlayerButton, javax.swing.GroupLayout.PREFERRED_SIZE, 91, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addContainerGap(161, Short.MAX_VALUE))
    );
    panelOneLayout.setVerticalGroup(
        panelOneLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(panelOneLayout.createSequentialGroup()
            .addGap(113, 113, 113)
            .addComponent(singlePlayerButton)
            .addGap(33, 33, 33)
            .addComponent(mulitPlayerButton)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, 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(panelOne, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(panelOne, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );

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

private void mulitPlayerButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                  
    multiPlayer();
}                                                 

private void singlePlayerButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                   
    singlePlayer();
}                                                  

public static void main(String args[]) {
    //<editor-fold defaultstate="collapsed" desc="Stuff/Look and Feel">
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Windows".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(MainFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }

    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new MainFrame().setVisible(true);
        }
    });
    //</editor-fold>
}

// Variables declaration - do not modify                     
private javax.swing.JSeparator firstRowLine1;
private javax.swing.JSeparator firstRowLine2;
private javax.swing.JSeparator firstRowLine3;
private javax.swing.JSeparator firstVerticalLine;
private javax.swing.JLabel jLabel1;
private javax.swing.JButton mulitPlayerButton;
private javax.swing.JPanel panelOne;
private javax.swing.JPanel panelTwo;
private javax.swing.JSeparator secondRowLine1;
private javax.swing.JSeparator secondRowLine2;
private javax.swing.JSeparator secondRowLine3;
private javax.swing.JSeparator secondVerticalLine;
private javax.swing.JButton singlePlayerButton;
// End of variables declaration                   

}

I am using NetBeans to design both panels.

Any help is appreciated!

Answer 1

您还可以添加：

MainFrame.this.repaint();