[news.eclipse.platform.swt] Re: question re. TableTree-viewer's refresh

[Tom Schindl <tom.schindl@xxxxxxxxxxxxxxx>]

Hi,

first of all TableTreeViewer should have been deprecated in 3.2 and you 
should better use a TreeViewer instead.

If you only want to refresh a specific part of your tree then you could 
use refresh(Object,boolean) and not the whole tree gets refershed on the 
other hand TreeViewer tries to preserve the selection which doesn't work 
 for you it seems.

I guess you are recreating *all* model elements from scratch everytime 
your content-providers getElements-method is called. If that's the case 
TreeViewer/TableTreeViewer is not able to preservet the selection and 
you need this your own. To see how this is done I'd suggest you read the 
JFace code yourself.

The methods of interest are:

- StructuredViewer#preservingSelection
- AbstractTreeViewer#setSelectionToWidget

Another resource might be a snippet I uploaed recently although it deals 
with TableViewer you might get the idea:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=164797

Tom

Michael Moser schrieb:
> I am using a table-tree viewer to observe the internal data structure of 
> some object.
> The use may collapse and expand this tree-view as desired to focus on 
> particular elements in the tree.
> If some data changes I fire a refresh on that tree (alas, there is no 
> method to signal specifically which element has changed).
>
> That refresh then always causes the entire tree to refresh - which I 
> wouldn't mind since the speed is not a problem(, yet) - but this refresh 
> also always expands/collapses the treeview to the expand level initially 
> chosen. That means, that the user's selections and changes re. focus are 
> lost and one has to search the particular tree-element one is interested 
> in again (and since there are lots of changes this is simply 
> unacceptable from a usability point of view).
>
> Can one somehow trigger a refresh, but only of those elements that are 
> currenly visible, i.e. leave the current expansion of subelements alone?
>
> Hope I could make myself clear...
>
> Michael