[news.eclipse.platform] Re: how to use treeViewer getExpandedElements me

[Ed Merks <merks@xxxxxxxxxx>]

Conor,

org.eclipse.ui.views.navigator.ResourceNavigator.restoreState uses it.


Conor O'Mahony wrote:
> Hi,
>
> I am using some of the EMF generated Editor code of my Model to 
> display a TreeViewer in a View. I have a filter on the TreeViewer that 
> filters the tree based on whatever the user selects in a dropdown. 
> When a user makes a particular selection in the dropdown, it may 
> result in an element being filtered out of the viewer, and what I want 
> to do is keep track of the expansion state of these elements that are 
> filtered out so that I can restore the expansion state when it gets 
> filtered back into the view.
>
> I have seen the Treeviewer getExpandedElements and setExpandedElements 
> methods in the TreeViewer API doc which I think will do the job, 
> however I could find any examples of their usage. I tried using them 
> within the select method of the ViewerFilter class, so that if an 
> element was being filtered out the viewer would retain a reference to 
> the expanded elements and then restore the expansion state when the 
> elements were filtered back in, but this did not work. Does anyone 
> know any examples of the correct usage of these methods or point out 
> where they should be used?
>
> Many thanks,
> Conor