layout that changes adding a JScrollList to a JList

Question

I am trying to create a GUI in java which contains a JComboBox and JList whose content changes depending on the selected item in the JComboBox.

I want to add a scroolPane to the JList. I'll show you the code and images to clarify the problem:

JPanel listPanel = new JPanel();

Hashtable<String, String[]> subItems = new Hashtable<String, String[]>();
JComboBox<String> tendina;
JList<String> subList;

GridBagConstraints c;

String ricevuti[] = {"Alex", "Ben", "Claire", "Dana", "Ellen", "Felicia", "Gary", "Hailey", "Imogen", "Jay", "Kate", "Alex", "Ben", "Claire", "Dana", "Ellen", "Felicia", "Gary", "Hailey", "Imogen", "Jay", "Kate"};
JList ricList = new JList(ricevuti);

String inviati[] = {"Lara", "Megan", "Nikole", "Oscar", "Paige", "Quentin", "Ralph", "Sara", "Thelma", "Victoria", "William"};
JList invList = new JList(inviati);

String ricInv[] = {"Seleziona un item..", "Ricevuti", "Inviati"};

Inbox() {

    //...

    listPanel.setLayout(new GridBagLayout()); 
    listPanel.setBackground(Color.BLUE);

    /*** ComboBox ***/
    tendina = new JComboBox<String>(ricInv);
    tendina.addActionListener(this);
    tendina.setEditable(false);
    c = new GridBagConstraints();
    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridwidth = 1;
    c.gridx = 0;
    c.gridy = 0;
    c.insets = new Insets(-295, 10, 0, 0); //top, left, bottom, right
    c.weightx = 1;
    listPanel.add(tendina, c);

    /*** Lista ***/
    subList = new JList<String>();
    subList.setPreferredSize(new Dimension(80, 280)); 
    subList.setVisibleRowCount(10);
    subList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    JScrollPane scrollList = new JScrollPane(subList);
    subItems.put(ricInv[1], ricevuti);
    subItems.put(ricInv[2], inviati);
    c = new GridBagConstraints();
    c.fill = GridBagConstraints.HORIZONTAL;
    c.gridwidth = 1;
    c.gridx = 0;
    c.gridy = 0;
    c.insets = new Insets(30, 10, 0, 0); //top, left, bottom, right
    c.weightx = 1;
    **[1]**listPanel.add(subList, c);
    **[2]**listPanel.add(scrollList, c);

    //...

}

The problem is that when I add the scrollList[2] to the listPanel, the layout is messed up. If I add the sublist [1] to listPanel, then the layout is right but obviously I don't have scrollList.

How can I add the scrollList without the layout is changed?

This is what happens if I add the subList to listPanel[1]: http://www.mediafire.com/view/daye4rkx1tyhwbq/sublist.png

This is what happens if I add the scrollList to listPanel[2]: http://www.mediafire.com/view/jfiky6j686e2h58/scroll.png

Thanks

---

As regards the height I realized that the problem depended from subList.setVisibleRowCount(16);.

But how can I adjust the width?

Answer 1

This is NOT the suggestion I gave you in your last posting: http://docs.oracle.com/javase/tutorial/uiswing/events/documentlistener.html

The JScrollPane containing the JList should be added to your GUI from the start using your desired layout.

Then you just change the data in the JList by using the setModel(...) method.