javax.swing.JComboBox

[Chris Lansdown]

Hi,

in javax.swing.JComboBox.contentsChanged:

  {
    // if first and last index of the given ListDataEvent are both -1,
    // then it indicates that selected item in the combo box data model
    // have changed. 
    if (event.getIndex0() == -1 && event.getIndex1() == -1)
      selectedItemChanged();
  }

it handles when the indexes are both -1, but it doesn't seem to handle any
other case. Is this indeed the correct behavior? In particular, this seems
to break MetalFileChooserUI, because
DirectoryComboBoxModel.setSelectedItem() always calls fireContentsChanged
as 

  fireContentsChanged(this, 0, items.size() - 1);

So, basically, when the popup list calls JComboBox.setSelectedIndex(...),
JComboBox never calls selectedItemChanged(), which never lets the listeners
in MetalFileChooserUI know that the selected item has changed.

Does this seem right?

DefaultComboBoxModel.setSelectedItem(...) is:

  {
    if (selectedItem == null)
      {
        if (object == null)
          return;
      }
    else
      {
        if (selectedItem.equals(object))
          return;
      }
    selectedItem = object;
    fireContentsChanged(this, -1, -1);    
  }

which is why anything which uses the default model works.

Incidentally, if you modify contentsChanged to run selectedItemChanged() on
other than -1, -1, you seem to get an infinite loop. I think that this is
fixable, however, if you put checks into MetalFileChooserUI's
DirectoryComboBoxAction.actionPerformed to only change the directory and
rescan if something has actually changed. I haven't verified this yet,
though.

Thanks,
-Chris

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