Jface TreeViewer add right click menu, depending on clicked node

Question

There is a good thread on how to correctly hook up a right-click menu to a Jface TreeViewer depending on the selected item.

I would like to show the right click menu depending on: if the right-click was on a node or into "empty space". The problem is that TreeViewer does not automatically clear the selection if you click into empty space. Is there any clean way how to achieve this?

My current approach would be to simply hook up a MouseListener to the tree with the following mouseDown method:

@Override
public void mouseDown(MouseEvent e) {
    TreeItem item = treeViewer.getTree().getItem(new Point(e.x, e.y));
    if (item == null) {
        treeViewer.getTree().deselectAll();
    }
}

This seems to work quite well. What do you think of this?

Note that there may not be any "empty space" at all, depending on how many items the `TreeViewer` contains. So this strikes be as bad UX design. — Baz, Sep 05 '14 at 10:08
@Baz I am not sure if I understand your point. If there is no empty space then everything should be fine because the user always clicks on a node? — user3726374, Sep 05 '14 at 10:21
So you don't want a context menu in the "empty space" because the user didn't right-click on a node? — Baz, Sep 05 '14 at 10:23

Baz · Accepted Answer · 2014-09-05T10:45:07.737

0

Ok, I found a dirty workaround. So if you really want to do it, here is a possible solution:

final Tree tree = viewer.getTree();

final Menu menu = new Menu(tree);
tree.setMenu(menu);
menu.addMenuListener(new MenuAdapter()
{
    @Override
    public void menuShown(MenuEvent e)
    {
        Point point = tree.toControl(Display.getDefault().getCursorLocation());
        boolean found = false;
        for (TreeItem item : tree.getItems())
        {
            for (int i = 0; i < tree.getColumnCount(); i++)
                if (item.getBounds(i).contains(point))
                    found = true;
        }

        System.out.println(found);
    }
});

edited Sep 05 '14 at 10:45

answered Sep 05 '14 at 10:07

Baz

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Okay, that even works without adding deselection. But probably as dirty as the deselection way :). – user3726374 Sep 05 '14 at 11:42
@user3726374 This solution is probably less performant, but I think it will confuse the user less :) – Baz Sep 05 '14 at 11:56

score 0 · Answer 2 · answered Jul 23 '15 at 08:40

How to add popup menu to your SWT/JFace TreeViewer
Hi, in your applications main class (that extends ApplicationWindow) in protected Control createContents(Composite parent) method you should add code like this:
//Author: Darius Kucinskas (c) 2008-2009
//Email: d[dot]kucinskas[eta]gmail[dot]com
//Blog: http://blog-of-darius.blogspot.com/
//License: GPL

// Create the popup menu
  MenuManager menuMgr = new MenuManager();
  Menu menu = menuMgr.createContextMenu(mTreeViewer.getControl());
  menuMgr.addMenuListener(new IMenuListener() {
    @Override
    public void menuAboutToShow(IMenuManager manager) {
      if(mTreeViewer.getSelection().isEmpty()) {
        return;
      }

      if(mTreeViewer.getSelection() instanceof IStructuredSelection) {
        IStructuredSelection selection = (IStructuredSelection)mTreeViewer.getSelection();
        DatabaseModelObject object = (DatabaseModelObject)selection.getFirstElement();

        if (object.getType() == DATABASE_OBJECT_TYPE.TABLE){
          manager.add(new ShowTableDataAction(SWTApp.this));
        }
      }
    }
  });

  menuMgr.setRemoveAllWhenShown(true);
  mTreeViewer.getControl().setMenu(menu);
DatabaseModelObject - is class from my problem domain (specific to my program). mTreeViewer - is object of TreeViewer class (JFace). Thanks, have a nice day!

Jface TreeViewer add right click menu, depending on clicked node

2 Answers2

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