commonPanel appear only in the last card with the CardLayout manager

[albert kao]

Why the commonPanel appear only in the last card with the CardLayout manager?
How to make the commonPanel appear in all the cards with the CardLayout manager?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class CardLayoutComboBox2 implements ItemListener {
    JPanel cards; // use CardLayout
    final static String BUTTONPANEL = "Card with JButtons";
    final static String ACTIONS2PANEL = "Card with different JButtons";
    final static String ACTIONS3PANEL = "Card with other JButtons";
    
    public void addComponentToPane(Container pane) {
        //Put the JComboBox in a JPanel to get a nicer look.
        JPanel comboBoxPane = new JPanel(); //use FlowLayout
        String comboBoxItems[] = { BUTTONPANEL, ACTIONS2PANEL, ACTIONS3PANEL };
        JComboBox cb = new JComboBox(comboBoxItems);
        JPanel commonPanel = new JPanel();
        cb.setEditable(false);
        cb.addItemListener(this);
        comboBoxPane.add(cb);

        commonPanel.add(new JTextField("Common"));
        commonPanel.add(new JButton("Common"));
        commonPanel.add(new JTextArea("Common2"));
        
        //Create the "cards".
        JPanel card1 = new JPanel();
        card1.add(commonPanel);
        card1.add(new JButton("Button 1"));
        card1.add(new JButton("Button 2"));
        card1.add(new JButton("Button 3"));
        
        JPanel card2 = new JPanel();
        card2.add(commonPanel);
        card2.add(new JButton("Button 1B"));
        
        JPanel card3 = new JPanel();
        card3.add(commonPanel);
        card3.add(new JButton("Button 3C"));
        
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        cards.add(card1, BUTTONPANEL);
        cards.add(card2, ACTIONS2PANEL);
        cards.add(card3, ACTIONS3PANEL);
        
        pane.add(comboBoxPane, BorderLayout.PAGE_START);
        pane.add(cards, BorderLayout.CENTER);
    }
    
    public void itemStateChanged(ItemEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getItem());
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("CardLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        //Create and set up the content pane.
        CardLayoutComboBox2 demo = new CardLayoutComboBox2();
        demo.addComponentToPane(frame.getContentPane());
        
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
    
    public static void main(String[] args) {
        /* Use an appropriate Look and Feel */
        try {
            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        } catch (UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        } catch (IllegalAccessException ex) {
            ex.printStackTrace();
        } catch (InstantiationException ex) {
            ex.printStackTrace();
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        /* Turn off metal's use of bold fonts */
        UIManager.put("swing.boldMetal", Boolean.FALSE);
        
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

[Michael Dunn]

it can only have one parent, so each time it is added to a new 'card', it is removed from the older card.

some options:
1) you can make commonPanel a class, then add a new instance of it to each card.
2) create a holding panel, cardlayout panel on top (or bottom), commonPanel in other area,
so only the 'cards' change

[albert kao]

Michael Dunn wrote:it can only have one parent, so each time it is added to a new 'card', it is removed from the older card.

some options:
1) you can make commonPanel a class, then add a new instance of it to each card.
2) create a holding panel, cardlayout panel on top (or bottom), commonPanel in other area,
so only the 'cards' change

Option 2:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class CardLayoutComboBox implements ItemListener {
    JPanel cards;
    final static String BUTTONPANEL = "Card with JButtons";
    final static String TEXTPANEL = "Card with JTextField";
    
    public void addComponentToPane(Container pane) {
        //Put the JComboBox in a JPanel to get a nicer look.
        JPanel comboBoxPane = new JPanel(); //use FlowLayout
        String comboBoxItems[] = { BUTTONPANEL, TEXTPANEL };
        JComboBox cb = new JComboBox(comboBoxItems);
        JPanel commonPanel = new JPanel();
        JTextField textFieldCommon = new JTextField("TextField Common", 20);
        cb.setEditable(false);
        cb.addItemListener(this);
        comboBoxPane.add(cb);

        commonPanel.add(textFieldCommon);
        
        //Create the "cards".
        JPanel card1 = new JPanel();
        card1.add(commonPanel);
        card1.add(new JButton("Button 1"));
        card1.add(new JButton("Button 2"));
        card1.add(new JButton("Button 3"));
        
        JPanel card2 = new JPanel();
        card2.add(commonPanel);
        card2.add(new JTextField("TextField", 20));
        
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        cards.add(card1, BUTTONPANEL);
        cards.add(card2, TEXTPANEL);
        
        pane.setLayout(new BoxLayout(pane, BoxLayout.Y_AXIS));
        pane.add(commonPanel);
        pane.add(comboBoxPane);
        pane.add(cards);
    }
    
    public void itemStateChanged(ItemEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getItem());
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("CardLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        //Create and set up the content pane.
        CardLayoutComboBox demo = new CardLayoutComboBox();
        demo.addComponentToPane(frame.getContentPane());
        
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
    
    public static void main(String[] args) {
        /* Use an appropriate Look and Feel */
        try {
            //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        } catch (UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        } catch (IllegalAccessException ex) {
            ex.printStackTrace();
        } catch (InstantiationException ex) {
            ex.printStackTrace();
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        /* Turn off metal's use of bold fonts */
        UIManager.put("swing.boldMetal", Boolean.FALSE);
        
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}