A individual class for each Card in java swing CardLayout

Question

For architecture and design purposes I would like to design my GUI with a class for each card in a Java Swing CardLayout. and then have a mainapp that builds the GUI. I am

Answer 1

very simple example that held Swing Objects generated from different Java Classes

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

public class OnTheFlyImageTest extends JFrame {

    private static final long serialVersionUID = 1L;
    private JPanel cardPanel;
    private CardLayout cardLayout;

    public OnTheFlyImageTest() {
        JPanel cp = new JPanel(new BorderLayout());
        cp.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        cardLayout = new CardLayout(5, 5);
        cardPanel = new JPanel(cardLayout);
        cp.add(cardPanel);
        for (int i = 0; i < 100; i++) {// Create random panels for testing.
            String name = "ImagePanel" + (i + 1);
            String image = (i & 1) == 0 ? "foo.gif" : "bar.gif";
            ImagePanel imgPanel = new ImagePanel(name, image);
            cardPanel.add(imgPanel, name);
            cardLayout.addLayoutComponent(imgPanel, name);
        }
        JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 5, 5));
        JButton prevButton = new JButton("< Previous");
        prevButton.setActionCommand("Previous");
        prevButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                cardLayout.previous(cardPanel);
            }
        });
        buttonPanel.add(prevButton);
        JButton nextButton = new JButton("Next >");
        nextButton.setActionCommand("Next");
        nextButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                cardLayout.next(cardPanel);
            }
        });
        buttonPanel.add(nextButton);
        JPanel temp = new JPanel(new BorderLayout());
        temp.add(buttonPanel, BorderLayout.LINE_END);
        cp.add(temp, BorderLayout.SOUTH);
        setContentPane(cp);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setTitle("Test");
        pack();
    }

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

            @Override
            public void run() {
                new OnTheFlyImageTest().setVisible(true);
            }
        });
    }
}

class ImagePanel extends JPanel {

    private static final long serialVersionUID = 1L;
    private String imgString;
    private JLabel imgLabel;

    public ImagePanel(String name, String imgString) {
        setName(name);
        this.imgString = imgString;
        setLayout(new BorderLayout());
        // Ensure size is correct even before any image is loaded.
        setPreferredSize(new Dimension(640, 480));
    }

    @Override
    public void setVisible(boolean visible) {
        if (visible) {
            System.err.println(getName() + ": Loading and adding image");
            ImageIcon icon = new ImageIcon(imgString);
            imgLabel = new JLabel(icon);
            add(imgLabel);
        }
        super.setVisible(visible);
        if (!visible) { // Do after super.setVisible() so image doesn't "disappear".
            System.err.println(getName() + ": Removing image");
            if (imgLabel != null) { // Before display, this will be null
                remove(imgLabel);
                imgLabel = null; // Hint to GC that component/image can be collected.
            }
        }
    }
}

Answer 2

Perhaps you want to give your class that uses the CardLayout a public loadCard method, something like

public void loadCard(JComponent component, String key) {
  cardHolderPanel.add(component, key);
}

where cardHolderPanel is the container that holds the cards.

Since your creating classes to act as cards, consider having them all extend from a base abstract class or an interface that has a method that allows this class to hold its own key String. Either that or simply use the JComponent name property to have a component hold its own key String, one that can easily be obtained via getName().

For a more detailed answer, you may need to give us more details on your current application and its structure.