Re: Connecting to Gtk::SpinButton::signal_scroll_event()?

[Jonathon Jongsma <jonathon quotidian org>]

On Thu, 2007-12-20 at 10:32 +0100, Toralf Lund wrote:
> Can I add an event hander for the "scroll event" on a SpinButton?
> 
> I've tried
> 
> bool ThisClass::OnScrollEvent(GdkEventScroll *event)
> {
>   cerr << "ThisClass::onScrollEvent\n";
> 
>   return false;
> }
> ...
> 
> spinbutton.signal_scroll_event().connect(sigc::mem_fun(*this, 
> &ThisClass::onScrollEvent));
> 
> (or rather, the equivalent code in a somewhat more complex class setup...)
> 
> This builds all right, but the handler doesn't seem to get called, i.e. 
> the text from "cerr" is never displayed. I also added
> 
> spinbutton.set_events(Gdk::ALL_EVENTS_MASK);
> 
> to make absolutely sure the event would be received, but it didn't make 
> any difference.
> 
> So, is there anything special about a SpinButton that prevents the above 
> from working? I mean, this is based on code that has worked in the past 
> for a simple Entry widget.
> 
> In case you wondered, I'm trying to override/add to the default scroll 
> handling in order to allow "spin" by different amounts depending on the 
> modifier state.
> 

I'm not sure, but I'm guessing this might be one of those signals where
you have to pass an extra 'false' parameter to connect() to tell it to
connect *before* the default handler (without that parameter, it
connects your handler *after* the default one)

-- 
Jonner