[news.eclipse.platform] Re: Does jface databinding support treeviewer?

[Matthew Hall <matthall@xxxxxxxxxxxxxxxxx>]

hao wrote:
> > contentProvider.getKnownElements is passed to the ListeningLabelProvider 
> constructor....
>
> I am sorry but still confusing about the contectprovider's 
> getKnowElements(). Let's start with steps of setting those providers:
> 1. Creat content provider,
> 2. Set content provider,
> 3. Create label provider,
> 4. Set label provider,
> 5. Set input.
>
> Before the input is set (at step 5), I believe the ObservableSet 
> returned by contentProvider.getKnownElements() is a empty set. The 
> PersonGroupLabelProvider implementation actually use another 2 sets of 
> ObservableSet - personPhoneKnownElements & 
> personPhoneGroupKnownElements. Only when addListenerTo() method is 
> called the elements are added into the 2 sets of ObservableSet - 
> personPhoneKnownElements & personPhoneGroupKnownElements. From the 
> implementation of PersonGroupLabelProvider, I do not see the super class 
> addListenerTo' addListenerTo() method is got called even when the 
> treeviewer input is set.
>
> Thanks!
> hao

The known elements set is populated by the content provider when the 
viewer elements are first discovered (after you set the input).  After 
that initial step, the content provider watches the input for additions 
/ removals in the collection, and adds / removes elements from the known 
elements set accordingly.

Matthew