How to Change java Cardlayout from another separate class

Question

Please I have been trying to switch CardLayout from another class (JPanel) which is one of the card on the CardLayout, I have search and made research about this for a very long time but found nothing helpful.

I have a CardLayout and two separate JPanels that I added to the CardLayout, now I want to be able to switch the cards after performing activities on the separate JPanel or separate class, so how do I switch the CardLayout from another class? my code below.

package myApp;
import java.awt.CardLayout;

public class TestmyCard extends javax.swing.JFrame {

/**
 * Creates new form TestmyCard
 */
public TestmyCard() {
    initComponents();
    jPanel1.add(new FirstCard(),"card3");
    jPanel1.add(new SecondCard(),"card4");
}

public void chgCard(String nwCard){
            CardLayout cl = (CardLayout)(jPanel1.getLayout());
   cl.show(jPanel1,nwCard);

}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jPanel2 = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();
    jPanel3 = new javax.swing.JPanel();
    jButton1 = new javax.swing.JButton();
    jButton2 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jPanel1.setName("Cards");
    jPanel1.setLayout(new java.awt.CardLayout());

    jPanel2.setName("card2");

    jLabel1.setText("second panel");

    javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
    jPanel2.setLayout(jPanel2Layout);
    jPanel2Layout.setHorizontalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel2Layout.createSequentialGroup()
            .addGap(119, 119, 119)
            .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 117, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(203, Short.MAX_VALUE))
    );
    jPanel2Layout.setVerticalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel2Layout.createSequentialGroup()
            .addGap(140, 140, 140)
            .addComponent(jLabel1)
            .addContainerGap(92, Short.MAX_VALUE))
    );

    jPanel1.add(jPanel2, "card2");

    jPanel3.setBackground(new java.awt.Color(153, 255, 153));

    jButton1.setLabel("First Btn");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jButton2.setLabel("Second Btn");
    jButton2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton2ActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
    jPanel3.setLayout(jPanel3Layout);
    jPanel3Layout.setHorizontalGroup(
        jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel3Layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jButton1)
            .addGap(18, 18, 18)
            .addComponent(jButton2)
            .addContainerGap(181, Short.MAX_VALUE))
    );
    jPanel3Layout.setVerticalGroup(
        jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel3Layout.createSequentialGroup()
            .addContainerGap(27, Short.MAX_VALUE)
            .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1)
                .addComponent(jButton2))
            .addGap(20, 20, 20))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 439, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(0, 0, Short.MAX_VALUE))
        .addGroup(layout.createSequentialGroup()
            .addGap(37, 37, 37)
            .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap())
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, 246, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 25, Short.MAX_VALUE)
            .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap())
    );

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

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt)    {                                         
    // TODO add your handling code here:
    CardLayout cl = (CardLayout)(jPanel1.getLayout());
   cl.show(jPanel1,"card3");
   //cl.next(jPanel1) ;
}                                        

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
    CardLayout cl = (CardLayout)(jPanel1.getLayout());
   cl.show(jPanel1,"card4");
}                                        

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /*
     * Set the Nimbus look and feel
     */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /*
     * If Nimbus (introduced in Java SE 6) is not available, stay with the
     * default look and feel. For details see
     * http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(TestmyCard.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /*
     * Create and display the form
     */
    java.awt.EventQueue.invokeLater(new Runnable() {

        public void run() {
            new TestmyCard().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.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
// End of variables declaration                   
}

FirstCard (separate jpanel)

package myApp;

public class FirstCard extends javax.swing.JPanel {

/**
 * Creates new form FirstCard
 */
public FirstCard() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    guName = new javax.swing.JTextField();
    guAddrs = new javax.swing.JTextField();
    jLabel14 = new javax.swing.JLabel();
    jLabel15 = new javax.swing.JLabel();
    guOccu = new javax.swing.JTextField();
    jLabel16 = new javax.swing.JLabel();
    guPhone = new javax.swing.JTextField();

    jLabel1.setText("Guarantee Name :");

    jLabel14.setText("Address :");

    jLabel15.setText("Occupation :");

    jLabel16.setText("Phone :");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel14)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(guAddrs, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel16)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(guPhone, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel15)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(guOccu, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel1)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(guName, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap(228, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(43, 43, 43)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel1)
                .addComponent(guName, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel15)
                .addComponent(guOccu, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(30, 30, 30)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel14)
                .addComponent(guAddrs, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel16)
                .addComponent(guPhone, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addContainerGap(135, Short.MAX_VALUE))
    );
}// </editor-fold>                        
// Variables declaration - do not modify                     
private javax.swing.JTextField guAddrs;
private javax.swing.JTextField guName;
private javax.swing.JTextField guOccu;
private javax.swing.JTextField guPhone;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel14;
private javax.swing.JLabel jLabel15;
private javax.swing.JLabel jLabel16;
// End of variables declaration                   
}

SecondCard (separate jpanel)

package myApp;

public class SecondCard extends javax.swing.JPanel {

/**
 * Creates new form SecondCard
 */
public SecondCard() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    jButton1 = new javax.swing.JButton();

    jLabel1.setText("this is the second card");

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

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(120, 120, 120)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jButton1)
                .addComponent(jLabel1))
            .addContainerGap(173, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(62, 62, 62)
            .addComponent(jLabel1)
            .addGap(18, 18, 18)
            .addComponent(jButton1)
            .addContainerGap(183, Short.MAX_VALUE))
    );
}// </editor-fold>

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here:
    TestmyCard nc = new TestmyCard();
    nc.chgCard("Card2");
}

// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
// End of variables declaration
}

Bougainville

For reference, here's a working example. – Nubilous

It appears that your jpanel2 is an instance of JPanel, though you don't want that, what you want is that jpanel2 to be an instance of SecondCard class. – Tippet

Answer 1

In your provided code, you never added FirstCard and SecondCard, to the JPanel having layout set to CardLayout. Since what you writing is this :

jPanel1.add(jPanel2, "card2");

here jPanel2 is an instance of JPanel, as you have initialized this in your TestmyClass Class, as :

jPanel2 = new javax.swing.JPanel();

instead I guess what you should be writing is :

jPanel2 = new SecondCard(passPanelWithCardLayoutAsArgument); // So that you can manoeuvre around b/w other JPanels

Here is a small working example for your help :

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

public class CardLayoutExample
{
    private JPanel contentPane;
    private MyPanel panel1;
    private MyPanel panel2;
    private MyPanel panel3;

    private void displayGUI()
    {
        JFrame frame = new JFrame("Card Layout Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setBorder(
            BorderFactory.createEmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new CardLayout());

        panel1 = new MyPanel(contentPane
                , Color.RED.darker().darker());
        panel2 = new MyPanel(contentPane
                , Color.GREEN.darker().darker());
        panel3 = new MyPanel(contentPane
                , Color.DARK_GRAY); 

        contentPane.add(panel1, "Panel 1"); 
        contentPane.add(panel2, "Panel 2");
        contentPane.add(panel3, "Panel 3");         

        frame.setContentPane(contentPane);      
        frame.pack();   
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new CardLayoutExample().displayGUI();
            }
        });
    }
}

class MyPanel extends JPanel 
{

    private JButton jcomp1;
    private JPanel contentPane;
    private Color backgroundColour;

    public MyPanel(JPanel panel, Color c) 
    {   
        contentPane = panel;
        backgroundColour = c;

        setOpaque(true);
        setBackground(backgroundColour);

        //construct components
        jcomp1 = new JButton ("Show New Panel");
        jcomp1.addActionListener( new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                CardLayout cardLayout = (CardLayout) contentPane.getLayout();
                cardLayout.next(contentPane);
            }
        });

        add(jcomp1);
    }

    @Override
    public Dimension getPreferredSize()
    {
        return (new Dimension(500, 500));
    }
}

LATEST EDIT : *Using your components and trying to put that into CardLayout, with this code : *

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

public class CardLayoutExample
{
    private JPanel contentPane;
    private FirstCard panel1;
    private SecondCard panel2;

    private void displayGUI()
    {
        JFrame frame = new JFrame("Card Layout Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setBorder(
            BorderFactory.createEmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new CardLayout());

        panel1 = new FirstCard(contentPane);
        panel2 = new SecondCard(contentPane);

        contentPane.add(panel1, "Panel 1"); 
        contentPane.add(panel2, "Panel 2");     

        frame.setContentPane(contentPane);      
        frame.pack();   
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new CardLayoutExample().displayGUI();
            }
        });
    }
}

class FirstCard extends javax.swing.JPanel 
{
    private javax.swing.JTextField addField;
    private javax.swing.JTextField nameField;
    private javax.swing.JTextField occField;
    private javax.swing.JTextField phoneField;
    private javax.swing.JLabel nameLabel;
    private javax.swing.JLabel addLabel;
    private javax.swing.JLabel occLabel;
    private javax.swing.JLabel phoneLabel;
    private JPanel centerPanel;
    private JPanel contentPane;
    private JButton nextButton;

    public FirstCard(JPanel cp) 
    {
        this.contentPane = cp;
        initComponents();
    }

    private void initComponents() 
    {
        setOpaque(true);
        setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        setBackground(Color.RED);
        setLayout(new BorderLayout(5, 5));

        nameLabel = new javax.swing.JLabel("Guarantee Name : ");
        nameField = new javax.swing.JTextField();   
        addLabel = new javax.swing.JLabel("Address : ");
        addField = new javax.swing.JTextField();        
        occLabel = new javax.swing.JLabel("Occupation : ");
        occField = new javax.swing.JTextField();
        phoneLabel = new javax.swing.JLabel("Phone : ");
        phoneField = new javax.swing.JTextField();
        centerPanel = new JPanel();
        nextButton = new JButton("Next");
        nextButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent ae)
            {
                nextButtonAction(ae);
            }
        });

        centerPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        centerPanel.setOpaque(true);
        centerPanel.setBackground(Color.WHITE);
        centerPanel.setLayout(new GridLayout(0, 2, 5, 5));
        centerPanel.add(nameLabel);
        centerPanel.add(nameField);
        centerPanel.add(addLabel);
        centerPanel.add(addField);
        centerPanel.add(occLabel);
        centerPanel.add(occField);
        centerPanel.add(phoneLabel);
        centerPanel.add(phoneField);

        add(centerPanel, BorderLayout.CENTER);
        add(nextButton, BorderLayout.PAGE_END);
    }                   

    private void nextButtonAction(ActionEvent ae)
    {
        CardLayout layout = (CardLayout)contentPane.getLayout();
        layout.next(contentPane);
    }
}

class SecondCard extends javax.swing.JPanel 
{

    private javax.swing.JButton nextButton;
    private javax.swing.JLabel textLabel;
    private JPanel contentPane;

    public SecondCard(JPanel cp) 
    {
        contentPane = cp;
        initComponents();
    }

    private void initComponents() 
    {

        setOpaque(true);
        setBackground(Color.GREEN.darker().darker());
        setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        textLabel = new JLabel("this is the second card", JLabel.CENTER);
        textLabel.setForeground(Color.WHITE);
        nextButton = new javax.swing.JButton();

        nextButton.setText("SwitchCard");
        nextButton.addActionListener(new ActionListener() 
        {
            public void actionPerformed(ActionEvent evt) 
            {
                jButton1ActionPerformed(evt);
            }
        });

        add(textLabel);
        add(nextButton);
    }

    private void jButton1ActionPerformed(ActionEvent evt) 
    {
        CardLayout layout = (CardLayout) contentPane.getLayout();
        layout.show(contentPane, "Panel 1");
    }
}

Method to clear fields

private void clearFields()
{
    Component components[] = centerPanel.getComponents();
    for (Component comp : components)
    {
        if (comp instanceof JTextField)
        {
            JTextField tfield = (JTextField) comp;
            tfield.setText("");
        }
        else if (comp instanceof JComboBox)
        {
            JComboBox cbox = (JComboBox) comp;
            cbox.setSelectedIndex(0);
        }
        else if (comp instanceof JRadioButton)
        {
            JRadioButton rbut = (JRadioButton) comp;
            rbut.setSelected(false);
        }
    }
}

And you will call this inside the actionPerformed() method of the Button, which will take you to the next Card.

Tippet

what if contentPane (jPanel) is private? the above will not work – Bougainville

See in my case contentPane is a private variable, and still it's working. See the 10th Line of CardLayoutExample Class. – Tippet

ok i change my i jPanel1 that contain the cardlayout to public and static access modifier and i was able to switch, so Kudos to you. – Bougainville

now the problem is when i switch the cardlayout panel and switch back the content of textfield and other things are still there, how do i reload or refresh the cardlayout? i try revalidate(), and validate(); but nothing happen? – Bougainville

Well while using CardLayout you don't really have to do revalidate()/repaint() sort of thingies of your own, they are done by the CardLayout internally. Now to answer what you are saying, I have to see your modified code, or let me put your classes to my example and demonstrate that to you. Give me around 15 - 20 mins – Tippet

@Bougainville : Now Please have a look again, now I had modified your code a bit, since I don't use NetBeans, I just changed the name of the variables, that's it and the ActionListener part for the Buttons and passed contentPane to both the classes. – Tippet

i have try it and discover that is still the same thing, the card switch but did not clear the content of the previous panel, let me make my self clear, if on the second card i fill a registration form, when i switch card and switch back again am not suppose to see those old stuff i fill again – Bougainville

Exactly, since what you looking at is the old JPanel itself, that's why the same old stuff is there. If you wanted to remove that stuff, then create a method, that will clear all fields, when you click on the Button that will take you to the next Card. – Tippet

Please do watch the latest edit, that might can give you some idea, how to clear things up. – Tippet