selecting a JTree node programmatically

[Alan Shiers]

Hi there,
Given a TreePath object, I need to know how to programmatically select a tree node on a JTree.
Here's the situation:
I have a simple text editor project which has a JTree on its interface representing the local file system. The program has a SaveAs dialog box which also has a duplicate JTree as the one on the main interface (directories only). As the user selects the directory in which they wish to save the open file in the SaveAs dialog box, I need somehow to programmatically cause the JTree on the main interface to correspondingly select the same directory. How is this done?
The whole point of this is so that I can then add a new leaf node to the tree at the specified directory location. I've tried simply setting the jTree1.setSelectionPath(...) method and even tried to call the valueChanged(...) method of the TreeSelectionListener object as you can see from the code snippet below, but none of these approaches have been successful.
Please advise,
Alan

public void createLeafNode()
{
  jTree1.repaint();
  if(path == null)
     return;
  jTree1.setSelectionPath(path);
  //SelectionListener.valueChanged(new TreeSelectionEvent(jTree1, path, true, oldLeadPath, newLeadPath));
  //System.out.println("path is: " + path.toString());
  DefaultTreeNode parent = getTreeNode(path);
  //System.out.println("parent is " + parent.toString());
  //Create the child node
  IconData idata = new IconData(ICON_LEAF, new FileNode(new SpecialFile(ref.FileOpen)));
  DefaultTreeNode node = new DefaultTreeNode(idata);
  parent.add(node);
  //Tell the JTree that the tree structure has changed
  jTree1.nodeStructureChanged(parent);
  path = path.pathByAddingChild(node);
  jTree1.scrollPathToVisible(path);
  //jTree1.repaint();}
}

[Joe Gilvary]

Your code example is confusing to me. Is JTree1 the JTree or is it an implementation of TreeModel? You call setSelectionPath() and nodeStructureChanged() on the same object. Are you subclassing JTree and implementing TreeModel yourself in a single class? Implementing TreeModel is a lot of work.
I have used setSelectionPath() successfully in a mouse listener without needing to call the SelectionEventListener from there at all. I think it's unusual to have to call that method yourself.
I've been able to add nodes to a JTree with code like this:

    public void drop(DropTargetDropEvent e) {
PCSMenuItem template = null;
xfer = e.getTransferable();
if(! xfer.isDataFlavorSupported(PCSMenuItem.PCS_MENU_ITEM_FLAVOR) && 
   ! xfer.isDataFlavorSupported(DataFlavor.stringFlavor)) {
System.err.println("What are you trying to pull? I only accept DataFlavor.stringFlavor or PCSMenuItem objects.");
e.rejectDrop();
return;
}
Point pt = e.getLocation();
TreePath destPath = getPathForLocation(pt.x, pt.y);
DefaultMutableTreeNode target = (DefaultMutableTreeNode)destPath.getLastPathComponent();
PCSMenuItem onMe = (PCSMenuItem) target.getUserObject();
try {
template = (PCSMenuItem)xfer.getTransferData(PCSMenuItem.PCS_MENU_ITEM_FLAVOR);
} catch (UnsupportedFlavorException ufe) {
System.err.println("Caught an UnsupportedFlavorException in PCSItemTree.drop(DropTargetDropEvent e).");
ufe.printStackTrace();
} catch (IOException ioe) {
System.err.println("Caught an IOException in PCSItemTree.drop(DropTargetDropEvent e).");
ioe.printStackTrace();
}
PCSMenuItem newbie = loader.insertMenuItem(onMe.getId(),template.getTitleId());
// Wrap the child in a DefaultMutableTreeNode and add it to the tree.
// Notify the tree that the model has changed
target.add(new DefaultMutableTreeNode(newbie));
myModel.nodeStructureChanged(target);
// Add the new child to the parent in the XML.
onMe.addChild(newbie);
return;
    }

(The loader persists menu structure data back to a database. myModel is an instance of DefaultTreeModel. xfer is declared Transferable and cast to my own class after it passes the transfer flavor checks.)
The O'Reilly "Swing" book and their "Java Foundation Classes in a Nutshell" were a lot of help to me with this stuff. Well worth the money, especially if you will be doing more of this kind of work.
HTH,
Joe