java - How to show different cards in a CardLayout?

Question

I looked at a code example that used this code:

cl.show(cardPanel, "" + (currentCard));

But when I use show I get a message in Eclipse that it's deprecated and I wonder if there is another way to show the different cards in the CardLayout when I click on the buttons? Below is the code for my CardLayout class. Suggestions are also welcome if some part of the code are bad practise. Thanks!

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

public class CardLayoutTest extends JFrame implements ActionListener {

// Ref
 private JPanel cardPanel, jp1, jp2, buttonPanel;
 private JLabel jl1, jl2;
 private JButton btn1, btn2;
 private CardLayout cardLayout;

// Konstruktor
 public CardLayoutTest()
 {
     setTitle("Test med CardLayout");
     setSize(600,400);

     cardPanel = new JPanel();
     buttonPanel = new JPanel();

     cardPanel.setLayout(cardLayout);

     jp1 = new JPanel();
     jp2 = new JPanel();

     jl1 = new JLabel("Card 1");
     jl2 = new JLabel("Card 2");

     jp1.add(jl1);
     jp2.add(jl2);

     cardPanel.add(jp1, "1");
     cardPanel.add(jp2, "2");

     btn1 = new JButton("Show Card 1");
     btn2 = new JButton("Show Card 2");

     buttonPanel.add(btn1);
     buttonPanel.add(btn2);

     getContentPane().add(cardPanel, BorderLayout.NORTH);
     getContentPane().add(buttonPanel, BorderLayout.SOUTH);

     btn1.addActionListener(this);
 }

     public void actionPerformed(ActionEvent event)
     {
        // ??? Show card 1 ???

        // ??? Show card 2 ???
     }

 public static void main(String[] args) {
     CardLayoutTest frame = new CardLayoutTest();

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    } 
}

Answer 1

• I can't see that Java7 show(Container parent, String name) or Java6 show(Container parent, String name) is depreciated

• depends if currentCard returns String from cl.show(cardPanel, "" + (currentCard));

EDIT (I tried your code example)

1.you forgot to initialize most important variable

private CardLayout cardLayout = new CardLayout();

2.then SSCCE could be

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

public class CardLayoutTest extends JFrame {

    private static final long serialVersionUID = 1L;
    private JPanel cardPanel, jp1, jp2, buttonPanel;
    private JLabel jl1, jl2;
    private JButton btn1, btn2;
    private CardLayout cardLayout = new CardLayout();

    public CardLayoutTest() {
        setTitle("Test med CardLayout");
        setSize(400, 300);
        cardPanel = new JPanel();
        buttonPanel = new JPanel();
        cardPanel.setLayout(cardLayout);
        jp1 = new JPanel();
        jp2 = new JPanel();
        jl1 = new JLabel("Card 1");
        jl2 = new JLabel("Card 2");
        jp1.add(jl1);
        jp2.add(jl2);
        cardPanel.add(jp1, "1");
        cardPanel.add(jp2, "2");
        btn1 = new JButton("Show Card 1");
        btn1.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                cardLayout.show(cardPanel, "1");
            }
        });
        btn2 = new JButton("Show Card 2");
        btn2.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                cardLayout.show(cardPanel, "2");
            }
        });
        buttonPanel.add(btn1);
        buttonPanel.add(btn2);
        add(cardPanel, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.SOUTH);
    }

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

            @Override
            public void run() {
                CardLayoutTest frame = new CardLayoutTest();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}