JList - deselect when clicking an already selected item

Question

If a selected index on a JList is clicked, I want it to de-select. In other words, clicking on the indices actually toggles their selection. Didn't look like this was supported, so I tried

list.addMouseListener(new MouseAdapter()
{
   public void mousePressed(MouseEvent evt)
   {
      java.awt.Point point = evt.getPoint();
      int index = list.locationToIndex(point);
      if (list.isSelectedIndex(index))
         list.removeSelectionInterval(index, index);
   }
});

The problem here is that this is being invoked after JList has already acted on the mouse event, so it deselects everything. So then I tried removing all of JList's MouseListeners, adding my own, and then adding all of the default listeners back. That didn't work, since JList would reselect the index after I had deselected it. Anyway, what I eventually came up with is

MouseListener[] mls = list.getMouseListeners();
for (MouseListener ml : mls)
   list.removeMouseListener(ml);
list.addMouseListener(new MouseAdapter()
{
   public void mousePressed(MouseEvent evt)
   {
      java.awt.Point point = evt.getPoint();
      final int index = list.locationToIndex(point);
      if (list.isSelectedIndex(index))
         SwingUtilities.invokeLater(new Runnable()
         {
            public void run()
            {
               list.removeSelectionInterval(index, index);
            }
         });
   }
});
for (MouseListener ml : mls)
   list.addMouseListener(ml);

... and that works. But I don't like it. Is there a better way?

Answer 1

Looking at the Example "ListSelectionModel: Enabling Toggle Selection Mode" here: http://java.sun.com/products/jfc/tsc/tech_topics/jlist_1/jlist.html

I have modified it slightly for multi-select list boxes (changed setSelectionInterval to addSelectionInterval) and eliminated a problem with re-selection if you click to de-select and move your mouse while the mouse is down (moved the gestureStarted check for both add and remove).

objList.setSelectionModel(new DefaultListSelectionModel() {
    private static final long serialVersionUID = 1L;

    boolean gestureStarted = false;

    @Override
    public void setSelectionInterval(int index0, int index1) {
        if(!gestureStarted){
            if (isSelectedIndex(index0)) {
                super.removeSelectionInterval(index0, index1);
            } else {
                super.addSelectionInterval(index0, index1);
            }
        }
        gestureStarted = true;
    }

    @Override
    public void setValueIsAdjusting(boolean isAdjusting) {
        if (isAdjusting == false) {
            gestureStarted = false;
        }
    }

});