Re: Nonstandard Check Button

[Paul Pogonyshev <pogonyshev gmx net>]

Carsten Burstedde wrote:
> > > I would like a check button where the checkbox does not automatically
> > > toggle its state when clicked.  I only need the clicked signal, and I
> > > will update the active state (and hence the checkbox) asynchronously.
> > > Is there some elegant way to do this?
> >
> > Catch the "clicked" signal and use g_signal_stop_emission().  Should
> > work I guess.
>
> With the following callback it doesn't help.  Maybe I need a
> GSignalEmissionHook? And how should I call g_signal_lookup etc.?
>
> static void
> check_clicked (GtkWidget *widget, gpointer data)
> {
>   g_print ("Clicked\n");
>   g_signal_stop_emission_by_name (widget, "clicked");
> }
>
> g_signal_connect (G_OBJECT (check), "clicked", G_CALLBACK
> (check_clicked), NULL);

In GTK+ sources (`gtkbutton.c') we can see that "clicked" signal is created
like this:

  button_signals[CLICKED] =
    g_signal_new ("clicked",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_FIRST | G_SIGNAL_ACTION,
                  G_STRUCT_OFFSET (GtkButtonClass, clicked),
                  NULL, NULL,
                  _gtk_marshal_VOID__VOID,
                  G_TYPE_NONE, 0);

So, any callback will be called after the class handler of the signal.  Then
you should subclass GtkCheckButton, override the `clicked' handler and not
call the handler of the parent class.

Paul