Re: JTree not updating af

"Qu0ll" <qu0ll@THRWHITE.remove-dii-this>
Wed, 27 Apr 2011 15:37:19 GMT
"Roedy Green" <> wrote in message

On Sun, 22 Jul 2007 23:22:08 +1000, "Qu0ll" <>
wrote, quoted or indirectly quoted someone who said :

However, when I call the same method on the same nodes in the transfer
handler nothing appears to happen so if you run the program again and drag
on to B for example nothing happens. C should be deleted.

did your remember to call
 public void fireTreeStructureChanged( Object source, TreePath path )
protected void fireTreeNodesChanged(
                                     Object source,
                                     Object[] path,
                                     int[] childIndices,
                                     Object[] children )

1. What's the difference between nodesRemoved() which I already call and
2. Why do there seem to be groups of 2 methods to do the same thing such as
those in (1) and those of the form nodesXXXX() and fireNodesXXXX()?
3. When I add either of these 2 lines to the code, A is deleted as well as C
which is still not correct:

fireTreeNodesRemoved(parent, new TreePath(root).getPath(), childIndices,
fireTreeStructureChanged(parent, new TreePath(root).getPath(), childIndices,

4. I have tried many combinations of the methods in (2) and none of them
gives the correct result. How do I get this to work inside the context of a
transfer handler? (Some do work from the button).

Revised code follows.

And loving it,

(Replace the "SixFour" with numbers to email me)

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Point;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.TransferHandler;
import javax.swing.WindowConstants;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class TreeDnDTestFrame extends JFrame {

 public static final DataFlavor MY_FLAVOR = new DataFlavor(String.class,

 class MyTransferable implements Transferable {
  private final DataFlavor[] flavors = {MY_FLAVOR};
  private DefaultMutableTreeNode data;

  public MyTransferable(final DefaultMutableTreeNode data) { = data;

  public Object getTransferData(DataFlavor flavor)
   throws UnsupportedFlavorException, IOException {
   if (flavor.equals(flavors[0])) {
    return (Object)data;
   } else {
    throw new UnsupportedFlavorException(flavor);

  public DataFlavor[] getTransferDataFlavors() {
   return (DataFlavor[])flavors.clone();

  public boolean isDataFlavorSupported(DataFlavor flavor) {
   for (DataFlavor df : flavors) {
    if (df.equals(flavor)) {
     return true;
   return false;

 class MyTransferHandler extends TransferHandler {
  protected Transferable createTransferable(JComponent c) {
   JTree tree = (JTree)c;
   Object o = tree.getSelectionPath().getLastPathComponent();
   DefaultMutableTreeNode node = (DefaultMutableTreeNode)o;
   return new MyTransferable(node);

  public boolean importData(TransferSupport support) {
   Point dropPoint = support.getDropLocation().getDropPoint();
   JTree tree = (JTree)support.getComponent();
   TreePath path = tree.getPathForLocation(dropPoint.x, dropPoint.y);
   if (path == null) {
    return false;
   } else {
    DefaultMutableTreeNode target =
    DefaultMutableTreeNode data = null;
    try {
     data =
    catch (UnsupportedFlavorException ufe) {
     return false;
    catch (IOException ioe) {
     return false;
    DefaultMutableTreeNode parent =
    System.out.println("data = " + data + ", target = " + target + ", parent
= " + parent);
    if (parent != null) {
     model.removeChildNode(parent, data);
   return true;

  public boolean canImport(TransferSupport support) {
   return true;

  public int getSourceActions(JComponent c) {
   return MOVE;

 private DefaultMutableTreeNode root, a, b, c;
 private JTree tree;
 private MyTreeModel model;

 public TreeDnDTestFrame() {

 public void setupModel() {
  root = new DefaultMutableTreeNode("ROOT");
  a = new DefaultMutableTreeNode("A");
  b = new DefaultMutableTreeNode("B");
  c = new DefaultMutableTreeNode("C");

 class MyTreeModel extends DefaultTreeModel {
  public MyTreeModel(DefaultMutableTreeNode root) {

  public void removeChildNode(DefaultMutableTreeNode parent,
DefaultMutableTreeNode child) {
   final int[] childIndices = {parent.getIndex(child)};
   final Object[] removedChildren = {child};
   nodesWereRemoved(parent, childIndices, removedChildren);
   fireTreeNodesRemoved(parent, new TreePath(root).getPath(), childIndices,

 public void defineGUI() {
  tree = new JTree();
  JScrollPane scrollPane = new JScrollPane();
  JPanel panel = new JPanel();
  setPreferredSize(new Dimension(800, 600));
  setMinimumSize(new Dimension(800, 600));
  setLayout(new BorderLayout());
  model = new MyTreeModel(root);
  tree = new JTree(root);
  tree.setTransferHandler(new MyTransferHandler());
  scrollPane = new JScrollPane(tree);
  JButton b = new JButton("Delete C");
  b.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent ae) {
    model.removeChildNode(a, c);
  panel = new JPanel();
  panel.setLayout(new CardLayout(8, 8));
  panel.add(scrollPane, "Tree");
  add(panel, BorderLayout.CENTER);
  add(b, BorderLayout.SOUTH);

 public static void main(String[] args) {
  EventQueue.invokeLater(new Runnable() {
   public void run() {
    new TreeDnDTestFrame().setVisible(true);

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