Thread: Removing a JPanel from another class

Hello everyone, I have once again aproached a problem on my journey to Java.

What I want to do:
I want to be able to remove a Jpanel from the main class but with another class. I'll try to show you what I mean:

The main class code:

package tictactoe;
import javax.swing.JFrame;
 
 
 
public class TicTacToe extends JFrame{
 
    public static void main(String[] args) {
 
 
        TheFrame window = new TheFrame();
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setSize(966,600);
        TheActualMenu menu = new TheActualMenu();
        window.addPanel(menu);
        window.setResizable(false);
        window.setVisible(true);
    }
 
 
}

the "TheFrame" code:

package tictactoe;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
 
 
 
 
public class TheFrame extends JFrame{
 
 
 
 
 
    public TheFrame(){
        super("Tic tac toe");
    }
 
 
    public void addPanel(JPanel panel){
        add(panel);
    }
 
    public void removePanel(JPanel panel){
        remove(panel);
    }
 
 
 
}

The class where the removing should happen, class TheActualMenu:

package tictactoe;
import java.awt.Graphics;
import javax.swing.JPanel;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.ImageIcon;
 
 
 
public class TheActualMenu extends JPanel{
    private Image background;
    private Image StartNormalState;
    private Image StartMouseHover;
    private Image StartPressed;
    private Image imageState;
 
 
 
 
 
    public TheActualMenu(){
 
        Handler theHandler = new Handler();
 
    }
 
 
 
 
 
 
 
 
    class Handler extends MouseAdapter{
 
 
 
        public Handler(){
 
 
        addMouseListener(new MouseAdapter(){
            @Override
            public void mouseClicked(MouseEvent e){
                if(e.getX() >= (966/2)-(imageState.getWidth(null)/2) 
                        && e.getX() <= (966/2)+(imageState.getWidth(null)/2) 
                        && e.getY() >= 32 && e.getY() <= 32+imageState.getHeight(null)){
 
                    //Event where The menu panel in TicTacToe gets removed
 
                }
 
            }
        });
 
 
 
 
 
 
        }
 
    }
 
 
}

I can't do TheFrame.removePanel(menu); since it's a JFrame and the constructor will create a new frame.


What should I do?

I hope this made sence and that the code isn't to sloppy.

No, what you're trying to do is not clear. If you want to replace one JPanel with another, alternating between them as needed, you should check out CardLayout.

Sorry it took me a while to respond(my internet was just too slow)

Okey looked at the cardlayout functions, found an example, and now I have this:

main code:

package tictactoe;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.*;
import java.awt.*;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
 
 
 
public class TicTacToe extends JFrame{
    public CardLayout cardlayout = new CardLayout();
    private static JPanel cardPanel, jp1, jp2, buttonPanel;
    private JLabel jl1, jl2;
    private JButton btn1, btn2;
    private static TheActualMenu menu = new TheActualMenu();
    private WindowMenu gameSession;
 
    public TicTacToe(){
        super("Tica taca toa");
 
        HandlerMenu handling = new HandlerMenu();
        menu = new TheActualMenu();
        gameSession = new WindowMenu();
 
        cardPanel = new JPanel();
        cardPanel.setLayout(cardlayout);
        jp1 = new JPanel();
        jp2 = new JPanel();
        jl1 = new JLabel("Card 1");
        jl2 = new JLabel("Card 2");
        buttonPanel = new JPanel();
        jp1.add(menu);
        jp2.add(gameSession);
        cardPanel.add(menu, "1");
        cardPanel.add(gameSession, "2");
        cardlayout.show(cardPanel, "1");
        btn1 = new JButton("Show Card 1");
 
        btn1.addActionListener(new ActionListener(){
            @Override
           public void actionPerformed(ActionEvent e){
               //cardlayout.show(cardPanel, "1");
               cardlayout.show(cardPanel, "1");
           } 
        });
 
 
 
 
        btn2 = new JButton("Show Card 2");
        btn2.addActionListener(new ActionListener(){ 
            @Override
            public void actionPerformed(ActionEvent e){
                //cardlayout.show(cardPanel, "2");
                changeToGame();
            }
        });
 
 
 
        buttonPanel.add(btn1);
        buttonPanel.add(btn2);
        add(buttonPanel, BorderLayout.SOUTH);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    }
 
 
    public void changeToGame(){
        cardlayout.show(cardPanel, "2");
    }
 
 
 
 
 
    public static void main(String[] args) {   
        EventQueue.invokeLater(new Runnable(){
 
 
 
        @Override
        public void run(){
          TicTacToe frame = new TicTacToe();
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setSize(966,600);
          frame.add(cardPanel);
          frame.setVisible(true);
        }});
 
 
    }
 
 
 
 
 
 
    class HandlerMenu extends MouseAdapter{
 
        public HandlerMenu(){
        addMouseListener(new MouseAdapter(){
            @Override
            public void mouseClicked(MouseEvent e){
                /*if(e.getX() >= (966/2)-(240/2) 
                        && e.getX() <= (966/2)+(240/2) 
                        && e.getY() >= 32 && e.getY() <= 131){*/
                    System.out.println("Now");
                    //changeToGame();
 
                //}
 
            }
        });
 
        }
 
    }
 
 
 
 
 
 
 
    }
 
 
 
The "the frame" code

the "TheFrame" code:

package tictactoe;
import java.awt.CardLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
 
 
 
 
public class TheFrame extends JFrame{
    private CardLayout cardLayout = new CardLayout();
    private JPanel cardPanel, jp1, jp2;
    private TheActualMenu menu;
    private WindowMenu gameSession;
 
 
    public TheFrame(){
        super("Tic tac toe");
 
        cardPanel = new JPanel();
        cardPanel.setLayout(cardLayout);
        jp1 = new JPanel();
        jp2 = new JPanel();
        menu = new TheActualMenu();
        jp1.add(menu);
        gameSession = new WindowMenu();
        jp2.add(gameSession);
        cardPanel = new JPanel();
        cardPanel.add(jp1, "1");
        cardPanel.add(jp2, "2");
        cardLayout.show(cardPanel, "1");
 
 
 
        add(cardPanel);
    }
 
 
    public void addPanel(JPanel panel){
        add(panel);
    }
 
    public void removePanel(JPanel panel){
        remove(panel);
    }
 
 
 
 
 
 
}

and the "Theactualmenu" class:

package tictactoe;
import java.awt.Graphics;
import javax.swing.JPanel;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.ImageIcon;
 
 
 
public class TheActualMenu extends JPanel{
    private Image background;
    private Image StartNormalState;
    private Image StartMouseHover;
    private Image StartPressed;
    private Image imageState;
 
 
 
 
 
 
    public TheActualMenu(){
        background = new ImageIcon("C:\\Users\\Elias Fredin\\Desktop\\placeholder\\TicTacToe\\TicTacToe\\src\\tictactoe\\TTTBackground.png").getImage();
        StartNormalState = new ImageIcon("C:\\Users\\NAME\\Desktop\\placeholder\\TicTacToe\\TicTacToe\\src\\tictactoe\\StartNotPressed.png").getImage();
        StartMouseHover = new ImageIcon("C:\\Users\\NAME\\Desktop\\placeholder\\TicTacToe\\TicTacToe\\src\\tictactoe\\StartMouseHover.png").getImage();
        StartPressed = new ImageIcon("C:\\Users\\NAME\\Desktop\\placeholder\\TicTacToe\\TicTacToe\\src\\tictactoe\\StartMousePressed.png").getImage();
        imageState = StartNormalState;
 
 
        Handler theHandler = new Handler();
 
    }
 
 
    @Override
    public void paint(Graphics g){
        super.paint(g);
        g.drawImage(background, 0, 0, null);
        g.drawImage(imageState, (966/2)-(imageState.getWidth(this)/2), 32, null);
    }
 
 
 
 
 
    class Handler extends MouseAdapter{
 
 
 
        public Handler(){
 
 
        addMouseMotionListener(new MouseAdapter(){ 
            @Override
            public void mouseMoved(MouseEvent e){
                if(e.getX() >= (966/2)-(imageState.getWidth(null)/2) 
                        && e.getX() <= (966/2)+(imageState.getWidth(null)/2) 
                        && e.getY() >= 32 && e.getY() <= 32+imageState.getHeight(null)){
                imageState = StartMouseHover;
                repaint();
                }
                else
                {
                imageState = StartNormalState;
                repaint();
                }
            }
        });
 
        addMouseListener(new MouseAdapter(){
            @Override
            public void mousePressed(MouseEvent e){
                if(e.getX() >= (966/2)-(imageState.getWidth(null)/2) 
                        && e.getX() <= (966/2)+(imageState.getWidth(null)/2) 
                        && e.getY() >= 32 && e.getY() <= 32+imageState.getHeight(null)){
                    imageState = StartPressed;
                    repaint();
                }
            }
        });
 
 
        addMouseListener(new MouseAdapter(){
            @Override
            public void mouseClicked(MouseEvent e){
                if(e.getX() >= (966/2)-(imageState.getWidth(null)/2) 
                        && e.getX() <= (966/2)+(imageState.getWidth(null)/2) 
                        && e.getY() >= 32 && e.getY() <= 32+imageState.getHeight(null)){
 
                    System.out.println(imageState.getHeight(null));//Event where the JPanel switch should happen
 
                }
 
            }
        });
 
 
        }
 
    }
 
 
 
 
}

SO now It works to switch between the panels by pressing the buttons, but how to I switch the pannels, by using the "changeToGame" function, from the class "TheActualFrame"?

The class responsible for displaying panels should have a method to change it's state, (switch panels). This method would be invoked when the time comes to switch panels. Call the method from where ever is needed, ("TheActualFrame").

I created the method "changeToGame()" in the class "TicTacToe" but I can't manage to acces it through other classes.

I can't do: TicTacToe tac = new TicTacToe();

tac.changeTogame();

since it would execute whats in the constructor.

Even if I create a new class with all the cardPanel content in it I'll still have to call it with: theCardPanelname CradPanels = new theCardPanelname();
and everything in the constructor gets executed.

And I tried to that but to use a method instead of the constructor and call that instead when adding it to the JFrame, but I failed :/

But I can't really say that it doesn't work since I'm a noob. Any advice?

Originally Posted by kinkita

I created the method "changeToGame()" in the class "TicTacToe" but I can't manage to acces it through other classes.

Why not? What did you try? What happened? ...Post the code so we can filter through it.

Originally Posted by kinkita

And I tried to that but to use a method instead of the constructor and call that instead when adding it to the JFrame, but I failed :/
But I can't really say that it doesn't work since I'm a noob. Any advice?

Yes, use a method. Again post what you have tried, what happened, and what you want to happen.

Your post doesn't make sense. If changeToGame() is a TicTacToe method, then tac.changeToGame() HAS to work and should have nothing to do with the constructor.

If you want one class to be aware of an instance of another class, you could always use a setter. For example, if an instance of CardPanels needs to be aware of a specific instance of TicTacToe, you could use a CardPanels method like:

setTicTacToeInstance( TicTacToe tic )
{
    this.tic = tic;
}

Or you could pass it to a CardPanels() constructor:

public CardPanel( TicTacToe tic )
{
    this.tic = tic;
 
    // etc., the rest of the constructor . . .
}

I managed to acces the class method "changeToGame". I added a System.out text to see if it worked and it did, but when I add the code "cardlayout.show(cardPanel, "2");" this error message comes up:

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: wrong parent for CardLayout
at java.awt.CardLayout.checkLayout(CardLayout.java:38 4)
at java.awt.CardLayout.show(CardLayout.java:506)
at tictactoe.TicTacToe.setCurrentPanel(TicTacToe.java :79)
at tictactoe.TheActualMenu$Handler$3.mouseClicked(The ActualMenu.java:96)
at java.awt.AWTEventMulticaster.mouseClicked(AWTEvent Multicaster.java:253)
at java.awt.Component.processMouseEvent(Component.jav a:6300)
at javax.swing.JComponent.processMouseEvent(JComponen t.java:3275)
at java.awt.Component.processEvent(Component.java:606 2)
at java.awt.Container.processEvent(Container.java:203 9)
at java.awt.Component.dispatchEventImpl(Component.jav a:4660)
at java.awt.Container.dispatchEventImpl(Container.jav a:2097)
at java.awt.Component.dispatchEvent(Component.java:44 88)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4575)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:4245)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:4166)
at java.awt.Container.dispatchEventImpl(Container.jav a:2083)
at java.awt.Window.dispatchEventImpl(Window.java:2489 )
at java.awt.Component.dispatchEvent(Component.java:44 88)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:674)
at java.awt.EventQueue.access$400(EventQueue.java:81)
at java.awt.EventQueue$2.run(EventQueue.java:633)
at java.awt.EventQueue$2.run(EventQueue.java:631)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectio nPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectio nPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$3.run(EventQueue.java:647)
at java.awt.EventQueue$3.run(EventQueue.java:645)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectio nPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 644)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:122)

Cross posted here at DIC.

It's difficult to help you without seeing updated code, preferably something that can be run, an SSCCE, that demonstrates the problem. Show us enough code to help you, the code the error refers to at a minimum. Otherwise, what would you expect us to do?

Taking a stab at your error message, "wrong parent for CardLayout," suggests you're mixing the parent and child relationship between the main container - the parent - and the cards it contains. For example, if you have two cards you want to alternate, there should be a third container in which to show the cards, the parent, to which the cards belong.

--- Update ---

In spite of my bluster, I took the code you posted at the other site and reduced it to something that could be run. Unfortunately, in the process I eliminated the error you've complained about and, in fact, never saw it. I also stripped the code of any real functionality other than switching between the two cards which have been given different colors to show the change. You might try adding your functionality back to the runnable framework I've provided, fixing breaks (if any) as you go. Starting with a bare bones framework and adding the desired functionality to it is a reasonable approach to building any complex project, providing a simple "test and fix" platform as you build. I recommend you try a similar approach for your next project. Let me know if you have any questions.

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
 
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class TicTacToe extends JFrame
{
    public CardLayout cardlayout = new CardLayout();
    public static JPanel cardPanel, buttonPanel;
    private JButton btn1, btn2;
    public TheActualMenu menu;
    public JPanel gameSession;
    public TicTacToe taca;
 
    // the default constructor
    // got rid of IniTicTacToe as I'm not sure of its purpose
    public TicTacToe()
    {
        // close the program when the TicTacToe frame is closed and
        // set other characteristics
        setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        setLocationRelativeTo( null );
        setSize(966,600);
 
        // create the first card
        menu = new TheActualMenu();
        menu.setOpaque( true );
        menu.setBackground( Color.RED );
 
        // create the second card
        gameSession = new JPanel();
        gameSession.setOpaque( true );
        gameSession.setBackground( Color.BLUE );
 
 
        cardPanel = new JPanel();
        cardPanel.setLayout(cardlayout);
        buttonPanel = new JPanel();
        cardPanel.add(menu, "1");
        cardPanel.add(gameSession, "2");
        cardlayout.show(cardPanel, "1");
 
        add(cardPanel);
 
        btn1 = new JButton("Show Card 1");
        btn1.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                cardlayout.show(cardPanel, "1");
            } 
        });
 
        btn2 = new JButton("Show Card 2");
        btn2.addActionListener(new ActionListener(){ 
            @Override
            public void actionPerformed(ActionEvent e){
                setCurrentPanel();
            }
        });
 
        buttonPanel.add(btn1);
        buttonPanel.add(btn2);
        add(buttonPanel, BorderLayout.SOUTH);
 
    } // end method IniTicTacToe()
 
    public void setCurrentPanel()
    {
        cardlayout.show(cardPanel, "2");
        System.out.println("It's working");
 
    } // end method setCurrentPanel()
 
    public static void main(String[] args)
    {   
        TicTacToe tictac = new TicTacToe();
 
        // moved the next two lines into the constructor
        //        tictac.add(cardPanel);
        //        tictac.setSize(966,600);
        tictac.setVisible(true);
 
    } // end method main()
 
} // end class TicTacToe
 
// I stripped this down to nothing, but you can fill back in as needed
class TheActualMenu extends JPanel
{
    public TheActualMenu()
    {
        // this statement causes an infinite loop, so has been commented out
        //        Handler theHandler = new Handler();
    }
 
 
    @Override
    public void paint(Graphics g)
    {
        super.paint(g);
    }
 
    class Handler extends MouseAdapter
    {
        private TicTacToe tac;
 
 
        public Handler()
        {
            // this sets up the infinite loop, and I'm not sure of its purpose
            tac = new TicTacToe();
 
            addMouseMotionListener(new MouseAdapter()
            { 
                @Override
                public void mouseMoved(MouseEvent e)
                {
                }
            });
 
            addMouseListener(new MouseAdapter()
            {
                @Override
                public void mousePressed(MouseEvent e)
                {
                }
            });
 
 
 
            addMouseListener(new MouseAdapter()
            {
                @Override
                public void mouseClicked(MouseEvent e)
                {
                }
            });
 
        } // end constructor
 
    } // end class Handler
 
} // end class TheActualMenu

Yes that works but the problem I am having is changing the cardlayout from another class, that is a different file.

I modifyed your code.

main code

package cardlayouttest;
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class CardlayoutTest extends JFrame
{
    public CardLayout cardlayout = new CardLayout();
    public static JPanel cardPanel, buttonPanel;
    private JButton btn1, btn2;
    public JPanel gameSession;
    public CardlayoutTest taca;
    public panel thePanel;
    public panelTwo theSecondPanel;
 
    // the default constructor
    // got rid of IniTicTacToe as I'm not sure of its purpose
    public CardlayoutTest()
    {
        // close the program when the TicTacToe frame is closed and
        // set other characteristics
        setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        setLocationRelativeTo( null );
        setSize(966,600);
 
        // create the first card
        thePanel = new panel();
        thePanel.setOpaque( true );
        thePanel.setBackground( Color.RED );
 
        // create the second card
        theSecondPanel = new panelTwo();
        theSecondPanel.setOpaque( true );
        theSecondPanel.setBackground( Color.BLUE );
 
 
        cardPanel = new JPanel();
        cardPanel.setLayout(cardlayout);
        buttonPanel = new JPanel();
        cardPanel.add(thePanel, "1");
        cardPanel.add(theSecondPanel, "2");
        cardlayout.show(cardPanel, "1");
 
        add(cardPanel);
 
        btn1 = new JButton("Show Card 1");
        btn1.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                cardlayout.show(cardPanel, "1");
            } 
        });
 
        btn2 = new JButton("Show Card 2");
        btn2.addActionListener(new ActionListener(){ 
            @Override
            public void actionPerformed(ActionEvent e){
                setCurrentPanel();
            }
        });
 
        buttonPanel.add(btn1);
        buttonPanel.add(btn2);
        add(buttonPanel, BorderLayout.SOUTH);
 
    } // end method IniTicTacToe()
 
    public void setCurrentPanel()
    {
        cardlayout.show(cardPanel, "2");
        System.out.println("It's working");
 
    } // end method setCurrentPanel()
 
    public static void main(String[] args)
    {   
        CardlayoutTest tictac = new CardlayoutTest();
 
        // moved the next two lines into the constructor
        //        tictac.add(cardPanel);
        //        tictac.setSize(966,600);
        tictac.setVisible(true);
 
    } // end method main()
 
} // end class TicTacToe

panel one:

package cardlayouttest;
 
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.event.*;
 
 
 
public class panel extends JPanel{
    private JButton butt;
    private CardlayoutTest card;
 
 
 
 
    public panel(){
        butt = new JButton("Switch");
        card = new CardlayoutTest();
 
        butt.addActionListener(new ActionListener(){
           @Override
           public void actionPerformed(ActionEvent e){
               card.setCurrentPanel();
           } 
        });
 
 
 
        add(butt);
 
 
 
 
    }
 
 
 
 
 
    @Override
    public void paint(Graphics g){
        super.paint(g);
        g.setColor(Color.yellow);
        g.fillRect(12, 23, 123, 123);
    }
 
 
 
}

Panel two:

package cardlayouttest;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
 
 
public class panelTwo extends JPanel{
 
 
 
 
 
 
        @Override
    public void paint(Graphics g){
        super.paint(g);
        g.setColor(Color.RED);
        g.fillRect(12, 23, 123, 123);
    }
 
 
 
}

The code "card.setCurrentPanel();" in panel one is what is bothering me. any advice?

I'm sorry if I'm being annoying, I'm not the best person to describe things.

And with the cross posting, I was verry desperate, it wont happen again.

Originally Posted by kinkita

And with the cross posting, I was verry desperate, it wont happe again.

We (among all forums) thank you in advance

What you've posted is nonfunctional. As was said on the other forum and in my comments to the code I posted, you can't call the constructor of a second class that calls the constructor of the first class. That creates an infinite loop and will eventually error out into a StackOverflow. Instead, pass an instance of the first class to the second class like this:

    public CardlayoutTest()
    {
        // close the program when the TicTacToe frame is closed and
        // set other characteristics
        setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        setLocationRelativeTo( null );
        setSize(966,600);
 
        // create the first card, passing an instance of this class
        thePanel = new MyPanel( this );
        thePanel.setOpaque( true );
        thePanel.setBackground( Color.RED );
 
    // . . . etc.

(Let me know if I need to post this whole class.) I explained this concept in post #7. If you didn't understand, you should have said so that we could go from there.

Then, you'll have to modify the class you called 'panel', but I changed the name to MyPanel as I've shown below. Class names should begin with capital letters and not be named the same as existing core Java classes.

package cardlayouttest;
 
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
 
// this class was called 'panel' in the code you posted 
public class MyPanel extends JPanel
{
//    private JButton butt;
    private CardlayoutTest card;
 
    // the constructor was changed to add the parameter CardlayoutTest card
    // and the JButton butt was removed because it was unnecessary/redundant
    public MyPanel( CardlayoutTest card )
    {
        this.card = card;
 
    } // end constructor MyPanel()
 
    @Override
    public void paint(Graphics g)
    {
        super.paint(g);
        g.setColor(Color.yellow);
        g.fillRect(12, 23, 123, 123);
    }
 
} // end class MyPanel

As always, let us know if you have additional questions.