CardLayout - How to Delete current card (Java Swing)

Question

How would one delete the current card that the user is on. I know how to go through a card layout using the next and previous function, but how would one remove the current frame that the user is on? For example, if I have a program where I am currently on the 3rd panel out of 5 total panels, how would I delete the current one which is the 3rd panel. Once you remove it, the next or previous one replaces it. I do not think removecurrentlayout can be used cause I am not removing a component. For example, in the code, how would I go about delete Card 3 if I am on that.

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Container;  
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class CardLayoutProg {

    public static void main(String[] args) {

        JFrame frame = new JFrame("CardLayout");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container contentPane = frame.getContentPane();
        JPanel buttonPanel = new JPanel();
        JButton nextButton = new JButton("Next");
        buttonPanel.add(nextButton);
        contentPane.add(buttonPanel, BorderLayout.SOUTH);
        final JPanel cardPanel = new JPanel();
        final CardLayout cardLayout = new CardLayout();
        cardPanel.setLayout(cardLayout);

        for (int i = 1; i <= 5; i++) {
          JButton card = new JButton("Card " + i);
          card.setPreferredSize(new Dimension(200, 200));
          String cardName = "card" + 123123;
          cardPanel.add(card, cardName);
        }

        contentPane.add(cardPanel, BorderLayout.CENTER);
        nextButton.addActionListener(e -> cardLayout.next(cardPanel));

        frame.pack();
        frame.setVisible(true);
  }
}

`String cardName = "card" + 123123;` Why is the code adding cards with the same name, in a loop? More widely, why do you see the need to delete a card? What is supposed to appear there once it *is* deleted? The solution might be as simple as to add a blank `JPanel` and flip to it once the user decides it is time to 'delete' the existing card (without actually removing the card) it might be that the best action is to simply change the values shown in any controls in the card back to default values (e.g. information is committed to storage).. — Andrew Thompson, Oct 03 '19 at 02:36

score 2 · Answer 1 · answered Oct 02 '19 at 21:39

2

If you look at the docs for Container, you will see that it has a remove() method. Since JPanel extends Container, it also has this method. You should familiarize yourself with these API docs to find this kind of information.

answered Oct 02 '19 at 21:39

Code-Apprentice

81,660
23
145
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camickr · Accepted Answer · 2019-10-03T01:49:36.377

Unfortunately the CardLayout does not tell you which card (JPanel) is currently being displayed.

Check out Card Layout Focus for a class that extends the CardLayout to provide this functionality.

You would use the getCurrentCard() method to access the panel currently being displayed.

Then once you get the card currently being displayed you can remove it from the parent panel using by the remove(...) method of the Container class.

You would just use the class as follows:

//final CardLayout cardLayout = new CardLayout();
final RXCardLayout cardLayout = new RXCardLayout();

The logic for your "Remove" button would be:

cardPanel.remove(cardLayout.getCurrentCard());

*Is this maybe a version dependend feature?* - it's an extension of the CardLayout found at the link provided in the answer. — camickr, Nov 23 '22 at 14:21

score -1 · Answer 3 · answered Oct 03 '19 at 06:00

-1

When you say index(3rd panel of 5 panels), you mean the name (String) of the component when it was inserted, right? I don't know any elegant way to do this, but you can try to get all the components in this container (parentComponent) and try to find the one that has the same name as your index. For example:

Component[] components = parentComponent.getComponents();

for(int i = 0; i < components.length; i++) {
    if(components[i].getName().equals(index)) {
        cardLayout.removeLayoutComponent(components[i]);
    }
}

answered Oct 03 '19 at 06:00

Java-Dev

438
4
20

(1-) the CardLayout manages the name internally. It is a constraint that is used when the card is added to the panel. Read the Swing tutorial on [How to Use CardLayout](https://docs.oracle.com/javase/tutorial/uiswing/layout/card.html) for information on how the layout manager works. – camickr Oct 03 '19 at 14:29

CardLayout - How to Delete current card (Java Swing)

3 Answers3