尽管使用了正确的布局管理器，但JButton仍未出现在JPanel上

Question

I have been working with Swing for a while now on my CS project and, this may sound redundant, but I am unable to pop in my JButton in my JPanel. There are two other buttons which follow the same code and they get displayed but this one I create just refuses to show up. The button is "View Question" button. Similar buttons like the OK and CANCEL work fine. Any help would be much appreciated. The code:

public class CatNodePicker {

private final JDialog dialog;
private String selectedNodeCode;
private XMLTreeNode selectedNode;
private JTree cat;

public CatNodePicker(Container container, JTree cat) {
    this.cat = cat;
    selectedNodeCode = null;
    selectedNode = null;
    dialog =new JDialog(findParentFrame(container), "Pick a LEAF node", true);
    JPanel buttonPanel = new JPanel();
    final JButton okButton = new JButton("OK");
    okButton.setEnabled(false);
    okButton.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            dialog.dispose();
        }
    });
    JButton cancelButton = new JButton("Cancel");
    cancelButton.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            selectedNodeCode = null;
            selectedNode = null;
            dialog.dispose();
        }
    });

    JButton viewQuestion = new JButton("View Question");
    viewQuestion.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            getQuestionLabel();
        }
    });

    buttonPanel.add(okButton);
    buttonPanel.add(viewQuestion);
    buttonPanel.add(cancelButton);

    cat.expandRow(1);
    JScrollPane jsp = new JScrollPane(cat);

    cat.addTreeSelectionListener(new TreeSelectionListener() {

        @Override
        public void valueChanged(TreeSelectionEvent e) {
            TreePath path=e.getNewLeadSelectionPath();
            if(path==null) {
                selectedNodeCode = null;
                selectedNode = null;
            }

            if (path.getLastPathComponent().equals(path.getPathComponent(1))) {
                selectedNodeCode = null;
                selectedNode = null;
            }
            else {
                XMLTreeNode n=((XMLTreeNode)path.getLastPathComponent());
                //System.out.println(n.toString());
                if(n.isLeaf() || n.isFilter() || n.isLayer()) {
                    selectedNodeCode = n.getCode();
                    selectedNode = n;
                    okButton.setEnabled(true);
                }
                else
                    okButton.setEnabled(false);
            }

        }
    });

    dialog.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
            selectedNodeCode = null;
            selectedNode = null;
            dialog.dispose();
        }
    });  

    dialog.getContentPane().add(jsp, BorderLayout.CENTER);
    dialog.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
    dialog.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    dialog.setSize(new Dimension(600,800));
    dialog.setLocationRelativeTo(null);
    dialog.pack();

}

public JComponent getQuestionLabel(){

    JLabel questionText= new JLabel("Question here");
    return questionText;

}

}

In short, I want a "View Question" button in between the OK and CANCEL buttons. Please help. Thank you so much :)

Answer 1

I'm posting this though I don't expect it to help very much. It illustrates that what you are doing works in the simple case, and that to answer your question we need to figure out where you deviate from the simple case (and from correct Swing usage).

import java.awt.BorderLayout;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JPanel;


public class Dialoger
{
    public static void main(String[] args)
    {
        Dialoger dialoger = new Dialoger();
        dialoger.go();
    }

    public void go()
    {
        JDialog jd = new JDialog();
        JButton one = new JButton("one");
        JButton two = new JButton("two");
        JButton three = new JButton("three");
        JPanel panel = new JPanel();
        panel.add(one);
        panel.add(two);
        panel.add(three);
        jd.add(panel, BorderLayout.SOUTH);
        jd.pack();
        jd.setVisible(true);
    }

}