[Glade-devel] feature request: additional callback like post-create-function

[Juan Pablo Ugarte]

On Thu, 2006-11-23 at 14:25 +0100, Oliver Nittka wrote:
> Hi,
> 
> some gtkmm-users (including me) are currently investigating on how to
> integrate gtkmm-style widgets into glade.
> 
> so far, we have already succeeded in getting the widgets into the glade
> palette and have glade set their (Glib::Property-based) properties.
> (this only involves a minor part of glue code.)
> 
> there remains, however, a problem that can only be solved by patching
> glade: whenever a GObject is created, it is necessary to call a function
> that wraps this GObject in its correspnding C++ class. this can be done
> from the widget's post-create-function and works wonderfully.
> 
> however, when loading the widgets from a glade file, the properties of
> the GObject get set before the wrapper function is called.
> at that time, the custom properties of the respective did already
> register a "set_property" function in their GWidgetClass, but as the
> respective Glib::Properties are not yet created, the values are silently
> lost and later, when the C++-object gets created, are set to their
> default values.

I was reading this thread
http://marc.theaimsgroup.com/?l=gtkmm&m=116376755831015&w=2
and i think i am understanding whats the problem.
I think if you override GObject construct() method in the glibmm wrapper
and do all you have to do there (register the gtype and create the
wrapper if apropiate) it would solve most .

so.. if glibmm does this in his custom constructor() method you will not
have to do it in the post-create function and you will not have problems
with libglade either.

> 
> so, loading a glade file results in all of the custom properties getting
> set to their default values.
> 
> a possible solution would be to introduce an additional callback
> function in the style of "post-create-function", that gets called after
> the GObject is created and before it's properties are set (i suppose in
> glade_widget_build_object() right after the call to g_object_newv()).

yep...

from gtk docs

"constructor ()  the constructor function is called by g_object_new() to
complete the object initialization after all the construction properties
are set. The first thing a constructor implementation must do is chain
up to the constructor of the parent class. Overriding constructor should
be rarely needed, e.g. to handle construct properties, or to implement
singletons."

BTW it would be cool to add a way to specify the type name to be
registered so YourCustomWidget get registered as "YourCustomWidget" and
not something like "glibmm__YourCustomWidget"

greets

Juan Pablo