[news.eclipse.platform.swt] Re: Problems with TreeViewer and java.io.Fil

[Stefan Zeiger <szeiger@xxxxxxxxxxxx>]

Karl Sand wrote:

> Running my code on a Windows 2000 system i always get the "javaw.exe, no 
> disk, no disk in floppy found" popup-window. when i click cancel or 
> continue the popup-window disappears. I tracked this behaviour down to 
> the use of listRoots(). But when i use java.io.File.listRoots() outside 
> my SWT-app in a Swing application everything works as it should and 
> there is no popup-window.

The problem is not listRoots() itself, it's calling list() on the File 
objects returned by listRoots(). For every node displayed in the tree, 
the TreeViewer calls the content provider's hasChildren() method so that 
it knows whether or not to display a "[+]" for expanding the node.

>    public boolean hasChildren(Object arg0) {
>        // Get the children
>        Object[] obj = getChildren(arg0);
>
>        // Return whether the parent has children
>        return obj == null ? false : obj.length > 0;
>    }

Just return true in this method. Then all nodes will initially be 
expandable. When you try to actually expand a node without any children, 
the "[+]" sign will disappear.

You could check if arg0 is one of the objects returned by listRoot() and 
only return true in these cases but the performance will be much better 
if you do it for all nodes.

--
Stefan Zeiger - Developer of Novocode Application Framework
Build SWT-based MVC GUIs via XML: http://www.novocode.com/naf/