JTree and dropdown options on right clicking nodes

Question

I\'m trying to use the JTree and implement different drop downs for all the parent nodes and the children nodes.

Here\'s what I\'ve done:

pmTree.addM         


        

Answer 1

You check the selected node:

DefaultMutableTreeNode node = (DefaultMutableTreeNode)pmTree.getLastSelectedPathComponent();

to see if you have a "parent" or a "child" node. You should select the node at the mouse position first, otherwise it will not be the right node. Call

TreePath path = pmTree.getPathForLocation(evt.getX(), evt.getY());
if (path != null) {
    pmTree.setSelectionPath(path);
} else {
    return;
}

at the beginning of treePopup. (methods in Java should start with a lower case letter!)

Answer 2

Awesome. I was successfully able to put the setSelectionPath() call inside the override of getPopupLocaiton(). I had been trying to do it inside the ActionListener of my JMenuItem to no avail.

public Point getPopupLocation( MouseEvent e ) {
    Point point = null;
    if( e != null ) {
        TreePath path = getClosestPathForLocation( e.getX(), e.getY() );
        setSelectionPath( path );
        point = e.getPoint();
    }
    return point;
}

Answer 3

Don't go as low-level as a MouseListener, instead use the api around componentPopupMenu. Doing so, the general approach is dynamically configure the componentPopup in the getPopupLocation method, some simple example snippet:

    JPopupMenu popup = new JPopupMenu();
    final Action action = new AbstractAction("empty") {

        @Override
        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub
        }
    };
    popup.add(action); 
    JTree tree = new JTree() {

        /** 
         * @inherited <p>
         */
        @Override
        public Point getPopupLocation(MouseEvent e) {
            if (e != null) {
               // here do your custom config, like f.i add/remove menu items based on context
               // this example simply changes the action name 
               TreePath path = getClosestPathForLocation(e.getX(), e.getY());
               action.putValue(Action.NAME, String.valueOf(path.getLastPathComponent()));
               return e.getPoint();
            }
            action.putValue(Action.NAME, "no mouse"); 
            return null;
        }

    };
    tree.setComponentPopupMenu(popup);