Re: have you seen my widgets?

[Iago Rubio <iago rubio hispalinux es>]

On Sun, 2005-02-20 at 11:39, handsome greg wrote:
> ok, let me just say that i'm "getting by" by doing things the way i
> am, but im more interested in the Right Way (tm) to do things
> according to gtk.  say i have a window with a vbox with a notebook
> with a page with a frame with a vbox with a combobox.  in my main
> window's vbox, i also have packed a button that says "go."  now when
> someone clicks "go" i want something to happen that deals with the
> currently selected item in the combo box.  currently im using a
> g_object_set_data "paper trail" to the combo box by essentially
> nesting a reference to each level of widgets into the previous one if
> that makes any sense.  that way i can get a pointer to the notebook
> from the button and a pointer to the frame from the notebook and so on
> until i find the combo box.  now, my app is actually a lot more
> complex and i need to decide on a method of doing things asap before
> it just gets outta control.  what are my alternatives (besides globals
> - not just static because they have to span multiple objects) ???  is
> there any way to just say combo =
> get_freakin_combobox_button("comboname"); ?  is there even a way to
> "name" widgets?  surely not everyone out there just keeps a pointer
> hanging around globally to every widget they plan on using from some
> other far away widget, right?

Glade uses some code that performs what you want.

It's implemented with the following set of functions/macros:

//////////// glade functions ////////////////////
#define GLADE_HOOKUP_OBJECT(component,widget,name) \
  g_object_set_data_full (G_OBJECT (component), name, \
    gtk_widget_ref (widget), (GDestroyNotify) gtk_widget_unref)

#define GLADE_HOOKUP_OBJECT_NO_REF(component,widget,name) \
  g_object_set_data (G_OBJECT (component), name, widget)

GtkWidget*
lookup_widget                          (GtkWidget       *widget,
                                        const gchar     *widget_name)
{
  GtkWidget *parent, *found_widget;

  for (;;)
    {
      if (GTK_IS_MENU (widget))
        parent = gtk_menu_get_attach_widget (GTK_MENU (widget));
      else
        parent = widget->parent;
      if (!parent)
        parent = g_object_get_data (G_OBJECT (widget),
"GladeParentKey");
      if (parent == NULL)
        break;
      widget = parent;
    }

  found_widget = (GtkWidget*) g_object_get_data (G_OBJECT (widget),
                                                 widget_name);
  if (!found_widget)
    g_warning ("Widget not found: %s", widget_name);
  return found_widget;
}
//////////// glade functions end ////////////////////

Then you "bind" all widgets you want to one top level widget, and you
can pick any other widget by name with lookup_widget().

As example:

GtkWidget *dialog;
GtkWiget *label;
GtkWidget *entry;
GtkWidget *button;

// ... build the UI ....

GLADE_HOOKUP_OBJECT_NO_REF (dialog, dialog,"dialog");
GLADE_HOOKUP_OBJECT (dialog, label, "label");
GLADE_HOOKUP_OBJECT (dialog, entry, "entry");
GLADE_HOOKUP_OBJECT (dialog, button, "button");

////

Then with any of those "binded" widgets you can pick a pointer from one
to another by name, as example:

dialog = lookup_widget(entry, "dialog");
entry = lookup_widget(button, "entry");
button = lookup_widget(label, "button");
label = lookup_widget(button, "label");

... and so on ...
-- 
Iago Rubio