Avoid resize of JList with setFixedCellWidth

Question

I have functionality in my application such that when I select an item in one list, information that is associated with the item appears in a second list. I notice however that the width of this second list box is changing according to the contents of the list. The result is that each time I select an item in the first list, the second list changes size.
I have tried using two methods, setFixedCellWidth(int value) and setPrototypeCellValue(" ") to control this behaviour. But the consequence is that although the second list does not change size, it also does not update with the information that is associated with the selected item in the first list.
So my question is how do these methods effect the repaint and revalidation of the panel when the listmodel of the list is updated?
Thanks so much.

Answer 1

Excuse dupe post if there is one. You have other problems if you are not seeing updates in second list when using setProto. . . method. See Below:
public class ListTest extends JFrame {
    Label label;
    DefaultListModel model;
    DefaultListModel targetModel;
    JList testList;
    JList targetList;
    public static void main( String[] args){
        new ListTest();
    public ListTest(){
        //super("Closing Test");
        getContentPane().setLayout(new BorderLayout());
        model = new DefaultListModel();
        for (int i = 0 ; i < 10 ;i++){
            model.addElement("test "+i);
        testList = new JList(model);
        testList.setDragEnabled(true);
        testList.setPrototypeCellValue("                                 ");
        testList.setTransferHandler(new ListTransferHandler());
        targetModel = new DefaultListModel();
        targetModel.addElement("test 6");
        testList.addListSelectionListener(new ListSelectionListener(){
            public void valueChanged(ListSelectionEvent lse){
                System.out.println(((String)testList.getSelectedValue()));
         JPanel centerPanel = new JPanel(new GridLayout(0,2,5,5));
        targetList = new JList(targetModel);
        targetList.setPrototypeCellValue("                                 ");
        targetList.setDragEnabled(true);
        targetList.setTransferHandler(new ListTransferHandler());
        JScrollPane targetJsp = new JScrollPane(targetList);
        JScrollPane jsp = new JScrollPane(testList);
        centerPanel.add(jsp);
        centerPanel.add(targetJsp);
        getContentPane().add(centerPanel);
        //setSize(200,300);
        addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent we){
                setVisible(false);
                dispose();
                System.exit(0);
        JPanel buttonPanel = new JPanel();
        JButton addButton = new JButton("add");
        addButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                Object[] selections = testList.getSelectedValues();
                for (int counter = 0 ; counter < selections.length; counter++){
                    String tester = (String)selections[counter];
                    targetModel.addElement(selections[counter]);
        JButton subButton = new JButton("subtract");
        subButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                if ( targetList.getSelectedIndex() >= 0){
                    targetModel.removeElementAt(targetList.getSelectedIndex());
        buttonPanel.add(addButton);
        buttonPanel.add(subButton);
        getContentPane().add(buttonPanel, BorderLayout.SOUTH);
                setVisible(true);
        pack();
}Cheers
DB