Problems with ListViews Drag and Drop

Question

I'm surprised that there isn't an Active X control that can do this more
easily? Would
be curious to find out if there is - although we aren't really embracing the
use of
them within Forte because it locks you into the Microsoft arena.
---------------------- Forwarded by Peggy Lynn Adrian/AM/LLY on 02/03/98 01:33
PM ---------------------------
"Stokesbary, Michael" <[email protected]> on 02/03/98 12:19:52 PM
Please respond to "Stokesbary, Michael" <[email protected]>
To: "'[email protected]'" <[email protected]>
cc:
Subject: Problems with ListViews Drag and Drop
I am just curious as to other people's experiences with the ListView
widget when elements in it are set to be draggable. In particular, I am
currently trying to design an interface that looks a lot like Windows
Explorer where a TreeView resides on the left side of the window and a
ListView resides on the right side. Upon double clicking on the
ListView, if the current node that was clicked on was a folder, then the
TreeView expands this folder and the contents are then displayed in the
ListView, otherwise, it was a file and it is brought up in Microsoft
Word. All this works great if I don't have the elements in the ListView
widget set to be draggable. If they are set to be draggable, then I am
finding that the DoubleClick event seems to get registered twice along
with the ObjectDrop event. This is not good because if I double click
and the current node is a folder, then it will expand this folder in the
TreeView, display the contents in the ListView, grab the node that is
now displayed where that node used to be displayed and run the events
for that as well. What this means, is that if this is a file, then Word
is just launched and no big deal. Unfortunately, if this happens to be
another directory, then the previous directory is dropped into this
current directory and a recursive copy gets performed, giving me one
heck of a deep directory tree for that folder.
Has anybody else seen this, or am I the only lucky one to experience.
If need be, I do have this exported in a .pex file if anybody needs to
look at it more closely.
Thanks in advance.
Michael Stokesbary
Software Engineer
GTE Government Systems Corporation
tel: [phone]
e-mail: [email protected]

Answer 1

here is the required code....
private static class TreeDragGestureListener implements DragGestureListener {
     public void dragGestureRecognized(DragGestureEvent dragGestureEvent) {
     // Can only drag leafs
     JTree tree = (JTree) dragGestureEvent.getComponent();
     TreePath path = tree.getSelectionPath();
     if (path == null) {
          // Nothing selected, nothing to drag
          System.out.println("Nothing selected - beep");
          tree.getToolkit().beep();
     } else {
          DefaultMutableTreeNode selection = (DefaultMutableTreeNode) path
               .getLastPathComponent();
          if (selection.isLeaf()) {
          TransferableTreeNode node = new TransferableTreeNode(
               selection);
          dragGestureEvent.startDrag(DragSource.DefaultCopyDrop,
               node, new MyDragSourceListener());
          } else {
          System.out.println("Not a leaf - beep");
          tree.getToolkit().beep();
}