From: Stalkern 2 <stalkern2 at tin.it>
Reply-To: stalkern2 at tin.it
To: Richard Jones <rich at annexia.org>
Subject: Re: Toggle button callback question
Date: Tue, 6 May 2003 16:50:10 +0200
References: <20030506141056.GB9761 at redhat.com>
In-Reply-To: <20030506141056.GB9761 at redhat.com>
Cc: lablgtk at kaba.or.jp
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Il  Tuesday 06 May 2003 16:10, Richard Jones ha scritto:
> I think this is a very simple question - but it seems to be defeating
> me nevertheless.
>
> I have code which looks like this:
>
> let menu_bold () =
>   (* I want this function to do two different things depending on whether
>      the toggle button is now active or inactive. *)
>
> let main () =
>   (* ..... *)
>
>   (* This is where I create my toolbar containing a toggle button. *)
>   let toolbar = GButton.toolbar ~packing:vbox#pack () in
>   toolbar#insert_toggle_button ~text:"Bold" ~callback: menu_bold ();
>
>
> The problem is that
>
> (a) The menu_bold cannot 'see' the button object, so it can't call
>     button#active to find the state.

associate a change in a ref value to your callback (and do the same for radio 
buttons)
>
> (b) I'd do this in C using a global variable to store the button object
>     or a forward prototype of some sort. Neither of these things seem
>     to exist in OCaml.

(see above...)

bye
Ernesto