Multiple CardLayouts Problem

[m3dabbag]

Hey, I'm pretty new to Java and I was wondering if anyone can help me out with figuring out a problem with using multiple cardlayouts. What I want to do is to have a combobox that has sections in it. Whenever the user chooses a section from the combobox, i want everything in the mainpanel (which has a cardlayout) to show. In the mainpanel, I have another combobox that contains testcategories. When the user chooses a test category, a bunch of checkboxes should show (which are placed in a jpanel with cardlayout). The problem is that when I choose anything from the testCategory combobox, the cards don't update and I can't see the checkboxes associated with whatever option they chose.

Here is the code (Please note that this works the way it is but still needs some work). Thanks in advance!

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

public class Testing implements ItemListener {
	
	private JFrame frame;
	private JComboBox testCategoryList;
	JComboBox sectionBox;
	private JPanel cards; 
	JPanel test1Panel;
	JPanel test2Panel;
	JPanel mainPanel = new JPanel(new CardLayout());
	private static Vector<JPanel> subPanels = new Vector<JPanel>();
	
	
	String[] testCategories = {"Test 1", "Test 2"};
	String[] sectionList = {"Section 1", "Section 2"};
	String selectedTests;
	
	public Testing() {
		//Main Frame
		frame = new JFrame("Testing");
		frame.getContentPane().setLayout(new BorderLayout());
		frame.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent we) {
				System.exit(0);
			}
		});
		
		sectionBox = new JComboBox(sectionList);
		sectionBox.addItemListener(this);
		
		//JPanel comboBoxPanel = new JPanel();
		testCategoryList = new JComboBox(testCategories);
		testCategoryList.addItemListener(this);
		//comboBoxPanel.add(testCategoryList);
		
		test1Panel = new JPanel();
		test1Panel.add(new JCheckBox("test1_1"));
		test1Panel.add(new JCheckBox("Test1_2"));
		test1Panel.add(new JCheckBox("Test1_3"));
		test1Panel.add(new JCheckBox("Test1_4"));
		
		test2Panel = new JPanel();
		test2Panel.add(new JCheckBox("test2_1"));
		test2Panel.add(new JCheckBox("test2_2"));
		test2Panel.add(new JCheckBox("test2_3"));
		test2Panel.add(new JCheckBox("test2_4"));
		
		cards = new JPanel(new CardLayout());
		cards.add(test1Panel, "Test 1");
		cards.add(test2Panel, "Test 2");
		
		for(int i = 0; i < testCategories.length; i++) {
			subPanels.add((JPanel)cards.getComponent(i));
		}
		
		mainPanel.add(subPanels.get(0), "Section 1");
		mainPanel.add(subPanels.get(1), "Section 2");
		mainPanel.add(subPanels.get(0), "Section 1");
		mainPanel.add(subPanels.get(1), "Section 2");
		
		frame.getContentPane().add(sectionBox, BorderLayout.PAGE_START);
		frame.getContentPane().add(testCategoryList, BorderLayout.BEFORE_LINE_BEGINS);
		//frame.getContentPane().add(cards, BorderLayout.CENTER);
		frame.getContentPane().add(mainPanel);
		frame.pack();
		frame.setSize(600, 500);
		frame.setVisible(true);
	}
	
	public void itemStateChanged(ItemEvent event) {
		if(event.getSource().equals(testCategoryList)) {
			CardLayout newCard = (CardLayout)(cards.getLayout());
			newCard.show(cards, (String)event.getItem());
			frame.repaint();
		} else {
			System.out.println("Section Changed");
		}
	}
	
	public static void main(String args[]) {
		new Testing();
	}
}

[DarrylBurke]

A Component can have only one parent. When you add test1Panel and test2Panel to mainPanel (twice!?!) they are automatically removed from cards.

Start simple. Create a panel with just two cards, each of which has an identifying label, and a combo box that allows you to change between them. Expand on that without again attempting to add the same component to more than one container.

db

[m3dabbag]

sorry, which part are you talking about? Is it this?

mainPanel.add(subPanels.get(0), "Section 1");
mainPanel.add(subPanels.get(1), "Section 2");
mainPanel.add(subPanels.get(0), "Section 1");
mainPanel.add(subPanels.get(1), "Section 2");

I know how to take care of a simple cardlayout but my problem is with a cardlayout within a cardlayout. If you could guide me somehow to create a cardlayout within a cardlayout with the proper initialization/components that would be awesome. I've been trying for a couple days now and I haven't had much success. Thanks.

[DarrylBurke]

What part of

A Component can have only one parent.

didn't you understand?

Don't try 'reusing' components, it doesn't work that way.

db

[m3dabbag]

The thing is, i need to show the testCateogry combobox and all the cards associated with it when the user chooses an item from the section combobox. So I need to show everything according to what they choose. If I don't put the cards in a panel, then I can't add them to the mainPanel and I need to show whatever is in the mainPanel according to what section they choose. It's basically a system where certain panels are shown according to what section they choose and certain panels are shown according to what category they choose within the section.

[m3dabbag]

I managed to solve the problem. All I did was add the cards panel to another jpanel called subpanels and then added the subpanels to the mainPanel and linked it with each section.