[Qt-interest] Qt MVC Questions

[Sean Harmer]

Willy P wrote:
> I have built a Model, a view and a delegate that represents a tree
> like data structure.
>
> Two related questions:
>
> 1)  Is there a way to hide TreeNodes in a view but show their
> children?  Basically I have data structures that are programatically
> useful but the user doesn't need to know about them.  So I'd like the
> view to show the invisible node's children as if they were children of
> the invisible node's parent.  I've tried setRowHidden() but it hides
> all the children as well.
>   
Try a custom class derived from QProxySortFilterModel.

> 2)  The opposite question.  Is there a way to have nodes appear in the
> view but not the model?  I basically want to add categorical
> separators.  In some situations I want them and in others I don't, but
> in no case do I need them in the raw model.
>   
Once again a custom proxy that sits between your source model and your 
custom view(s) will be the way to go. I think that there is already some 
classes in KDE that do this. Yes, check out KCategorizedView and 
KCategorizedSortFilterProxyModel:

http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKCategorizedView.html
http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKCategorizedSortFilterProxyModel.html

They should do what you need for (2) without any work needed on your part.

Sean