Handle "add child to Gtk.Box" event

Question

As I am aware, I can subscribe to Gtk.Box signal "add child":

box.connect("add", self.__add_to_switch_list)

which will be called when I add child by box.add(child), and it's working.

But how I would do the same with box.pack_start() method?

Answer 1

There is no way.

---

"add" is only emitted when you call GtkContainer.add(). The first handler of this signal is subclass' method. For example, GtkBox does this :

/* gtk_box_class init: */
container_class->add = gtk_box_add;
...

static void
gtk_box_add (GtkContainer *container,
         GtkWidget    *widget)
{
  GtkBoxPrivate *priv = GTK_BOX (container)->priv;

  gtk_box_pack_start (GTK_BOX (container), widget,
                      priv->default_expand,
                      TRUE,
                      0);
}