How to disable buttons in GTK3
For specific control, I think you can use "set_sensitive":
var button = new Gtk.Button.with_label("Hello");
button.set_sensitive(false); // true to enable the button
gtk_widget_set_sensitive (widget, FALSE);
Note that if you need to check whether a widget is sensitive, gtk_widget_get_sensitive()
returns the value set with the above function and gtk_widget_is_sensitive()
will tell you whether the widget really is sensitive -- this is affected by parent widgets sensitivity as well.