Re: [Vala] How to call base constructors

[Adi Roiban <adi roiban ro>]

În data de Mi, 06-05-2009 la 17:48 +0000, Jan Hudec a scris:
> Vlad Grecescu <b100dian    > writes:
> > On Mon, May 4, 2009 at 4:40 PM, Adi Roiban 
> <adi roiban ro> wrote:
> > > I'm trying to extend the Gtk.CheckMenuItem and unfortunately there are
> > > no set_label or set_mnemonic methods.
> > > I was thinking to call the base constructor, but instead of
> > > gtk_check_menu_item_new_with_label, vala generates
> > > gtk_check_menu_item_construct_with_label
> > > Do you know how can I call a base constructor?
>
> You don't want to call gtk_check_menu_item_new_with_label, because it's
> not a constructor! It's an allocator, which is not the thing you want.
True! 

My goal is to call the contructor callend for
gtk_check_menu_item_new_with_label

> GObject is limited to initializing base objects is by setting their
> construct-time properties. Unfortunately the check_menu_item does not seem to
> have one for label or mnemonic, so you'll have to manually
>    add(new Gtk.Label(...))
> in your constructor.
That's what I did... but I don't want to recreate the widget.
It is not feasible for more complex widgets.

> Other thing is, that you should only ever subclass widgets when you want to
> modify their look & feel, not to implement functionality. And if you are to
> override the look & feel, you probably don't want to add a plain label, no?
> So you should not need those base constructors in your case anyway.
True!

> Functionality is better implemented by connecting handlers to the signals
> emited by the widget, where the handlers are implemented either in a class
> representing the document or dialog. You can also take advantage of the
> GtkAction (GtkToggleAction in your case) class, that can connect to or serve
> as factory for menu items, buttons and toolbar buttons and inherit that to
> provide your common functionality.
True!
Basicaly, that what I wanted to do .... but I failed.

For example in the case of MenuItem, we have the "activated" signal and
there is not way to pass userdata when connecting the signal.

The method called for the "activate" signal will only receive a pointer
to the MenuItem... and I can not pass userdata.

Maybe this is a problem with GTK bindings for Vala.


Thank you for your help!

Cheers!
-- 
Adi Roiban