[vox-tech] gtk question - gtk notebook page creation from a callback

[Gabriel Rosa]

On Thu, 23 May 2002, Peter Jay Salzman wrote:

>
> i'd like to add a page to a gtk notebook from a menuitem activation.
> here's what i have (much snippage):
>

[snip]

>
> so when someone clicks "view sprites", it calls back
> viewSpritesItemCallback.   what i'd like to do is call:
>
>   gtk_notebook_append(GtkNotebook *notebook,
>      GtkWidget *ChildToEmbedInPage,
>      GtkWidget *PageLabel)
>
> but if this is called within the callback, ChildToBeEmbededInPage and
> PageLabel both go out of scope when the callback ends.  if i dynamically
> allocate static memory, the pointers are lost.
>
> all i can think of is making everything global, but that can't be the
> only answer.   i'm a total gui novice -- are we expected to use lots of
> global variables in gui programming?

What I usually do for my FLTK stuff is put all the interface widgets into
an Interface class, and pass a pointer to the interface class using the
(void *) field in the callback. You could also do this on a widget-by-widget
basis (ie, pass a widget * as the arguments to the callback).

It's non-elegant, but it works.

>
> any ideas on how i can make the callback add a page to the notebook?
>

-Gabe