Re: [Q] redisplaying the items of a choice widget

davef@xanalys.com writes:

>       Is it possible to redisplay the items of a choice widget
>       (e.g. LIST-PANEL) without having to change the COLLECTION-ITEMS slot?
>
>    I don't think it is. 
>
>    - n
>
> Correct. 

Is this because LIST-PANEL caches the items to be displayed
internally?

>       e.g:
>
>       (setq items '(foo bar biz))
>       (setq items-view (make-instance 'capi:list-panel :items items))
>       (capi:contain items-view)
>       (setf (car items) 'quux)
>
>       Ideally, at this point I'd like to be able to say something like:
>
>       (redisplay items-view)
>
>       and have the `items-view' LIST-PANEL redraw the visible items.  
>
> But there's various things to do behind the scenes, including setting
> the representation and updating the sort order, and these are all done
> by (SETF CAPI:COLLECTION-ITEMS).

I'm not specifying any explicit sort order, does that make a
difference?

>                                                                      A
>       broader question would be whether any kind of observer functionality
>       is implemented in the CAPI widgets?
>
> What does observer mean here?

I was referring to the Observer design pattern, as realized in
Model-View, where object A (usually a view) "observes" (or is a
dependent of) object B (usually a model), and responds to change
notifications from object B, by redrawing itself (usually). If
LIST-PANEL provided a way to redisplay part or all of its contents,
then it would be pretty easy to add the observer capability as a
mixin.

On a related but separate note, I didn't see any way for specifying a
different visual representation (i.e. font or color specification) for
each item (first item in Blue Italics, second in Red Bold etc.) in the
LIST-PANEL collection-items. Is that a correct?

Thanks.

-ram