Re: g_signal_connect -- "button-press-event" vs "pressed"

[Micah Carrick <email micahcarrick com>]

Start with the API documentation for a GtkButton: 
http://library.gnome.org/devel/gtk/stable/GtkButton.html

Scroll down to "Signals" to see each signal you can connect a callback 
to for a GtkButton as well as the prototype for writing such a callback 
function. That is where "pressed" is coming from... the GtkButton.

You can also look at the section called "Object Hierarchy" in the API to 
see which objects a GtkButton is derived from. You can also use the 
signals for any of those objects. If you were to click on GtkWidget, 
you'll find the "button-press-event" signal there with the description:

" The ::button-press-event signal will be emitted when a button 
(typically from a mouse) is pressed."

So as you can see, the "pressed" signal from GtkButton is what you want 
to connect to for a user clicking a button. If you want to capture the 
mouse clicking on a widget... any widget... you use "button-press-event".

Whenever you find a signal that you don't know to which object it 
belongs, one easy way out is to search for it in Devhelp.

- Micah Carrick

 Developer - http://www.micahcarrick.com
 GTK+ Forums - http://www.gtkforums.com



Charles Packer wrote:
> If I code a button widget like this (I'm using the version
> of GTK that came with Fedora Core 5)...
>
> 	GtkWidget *B = gtk_button_new_with_label (Label);
> 	g_signal_connect (GTK_OBJECT (B), "button-press-event",
>                 G_CALLBACK (Happened), "HELLO");
>
> and the callback is this...
>
> 	Happened (GtkWidget *W, gpointer Data) {
> 		g_print ("ButtonHappened...|%s|\n", (char *) Data);
> 	}
>
> when Happened is executed, it doesn't print the data. That is, I get 
> "ButtonHappened...||". But when I replace the parameter 
> "button-press-event" in the call to g_signal_connect with "pressed", 
> on execution the printout is as desired, "ButtonHappened...|HELLO|". 
>
> Now, "button-press-event" is in lists of event types such as you 
> find in the GTK 2.0 tutorial at 
> http://www.gtk.org/tutorial/a2769.html
>
> As for "pressed", I don't know where I got it. It must have 
> come along with some example I found in a newsgroup or on the Web.
> I haven't been able to find an event-type list anywhere that 
> contains it, so I can't solve the mystery of why I get what I 
> want when I use that parameter, but not with the "legitimate" 
> parameter.
>
> --     
> Charles Packer
> http://cpacker.org/whatnews
> mailboxATcpacker.org 
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>