🚀 go-pugleaf

Your question isn't very simple to answer just like that. But there is some
methods provided to dynamically change a tree:
- DefaultTreeModel class
    * removeNodeFromParent(..)
    * insertNodeInto(...)
    * reload(...)
    * setRoot(...)
- DefaultMutableTreeNode
    * removeAllChildren()

Here is a simple example for how you can use some of these methodes
class DynamicTreeDemo
===============================================
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;

public class DynamicTreeDemo extends JFrame {
    private int newNodeSuffix = 1;

    public DynamicTreeDemo() {
  super("Dynamic Tree Demo");
  Container contentPane = this.getContentPane();
    // Create final instance of this class, see below
    final DynamicTree treePanel = new DynamicTree();

        JButton addButton = new JButton("Add");
        addButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                treePanel.addObject("New Node " + newNodeSuffix++);
            }
        });

        JButton removeButton = new JButton("Remove");
        removeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                treePanel.removeCurrentNode();
            }
        });
        JButton clearButton = new JButton("Clear");
        clearButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                treePanel.clear();
            }
     });

        // Lay everything out.
        //............
      }

    public static void main(String[] args) {
  DynamicTreeDemo dtd = new DynamicTreeDemo();
        dtd.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
}

class DynamicTree
==========================================
import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;

public class DynamicTree extends JPanel {
    protected DefaultMutableTreeNode rootNode;
    protected DefaultTreeModel treeModel;
    protected JTree tree;
    private Toolkit toolkit = Toolkit.getDefaultToolkit();

    public DynamicTree() {
  this.setLayout(new BorderLayout());
        rootNode = new DefaultMutableTreeNode("Root Node");
        treeModel = new DefaultTreeModel(rootNode);

        tree = new JTree(treeModel);
        tree.getSelectionModel().setSelectionMode
                  (TreeSelectionModel.SINGLE_TREE_SELECTION);
        JScrollPane scrollPane = new JScrollPane(tree);
        add(scrollPane, BorderLayout.CENTER);
    }

    /**
  * Remove all nodes except the root node.
  */
    public void clear() {
        rootNode.removeAllChildren();
        treeModel.reload();
    }

    /**
  * Remove the currently selected node.
  */
    public void removeCurrentNode() {
  DefaultMutableTreeNode currentNode =
(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
  if (currentNode != null) {
   DefaultMutableTreeNode parentNode =
(DefaultMutableTreeNode)currentNode.getParent();
   if (parentNode != null) {
    treeModel.removeNodeFromParent(currentNode);
    return;
   }
  }
  // Either there was no selection, or the root was selected.
  toolkit.beep();
    }

    /**
  * Add child to the currently selected node.
  */
    public DefaultMutableTreeNode addObject(Object child) {
  DefaultMutableTreeNode parentNode =
(DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
  if (parentNode == null) {
   parentNode = rootNode;
  }
  DefaultMutableTreeNode childNode =
    new DefaultMutableTreeNode(child);
  treeModel.insertNodeInto(childNode, parentNode,
         parentNode.getChildCount());
  // Make sure the user can see the lovely new node.
  tree.expandPath(new TreePath(parentNode.getPath()));
  tree.scrollPathToVisible(new TreePath(childNode.getPath()));

  return childNode;
    }
}

Puuh this was much, hopefully you get some helpinformation about a dynamic
JTree

// Andreas

Jan Lacluyse <jan.lacluyse@teleatlas.com> wrote in message
news:38FAE449.E6FF274D@teleatlas.com...
> Hoi,
>
> Can somebody tell me how I can dynamically build a JTree.
> For example a directory structure on a PC.
>
> Jan
>