Re: Item Factory Entry Callback Data

[Tim Janik <timj gtk org>]

On Wed, 18 Nov 1998, Shaw Terwilliger wrote:

> I've got a basic design question about the item factory's
> callback mechanisms.  As it stands, it looks like the factory
> only allows a single callback_data item across all factory
> items.  Each entry has a callback_type parameter, which 
> looks like it would hold some very basic callback data dear 
> to each entry, but there doesn't appear to be a way to 
> assign real data (through a pointer) to each individual item.
> 
> >From gtk/gtkitemfactory.h:
> 
> void    gtk_item_factory_create_item    (GtkItemFactory        
> *ifactory,
>                                          GtkItemFactoryEntry    *entry,
>                                          gpointer               
> callback_data,
>                                          guint                  
> callback_type);
> void    gtk_item_factory_create_items   (GtkItemFactory        
> *ifactory,
>                                          guint                  
> n_entries,
>                                          GtkItemFactoryEntry   
> *entries,
>                                          gpointer               
> callback_data);
> void    gtk_item_factory_create_items_ac(GtkItemFactory        
> *ifactory,
>                                          guint                  
> n_entries,
>                                          GtkItemFactoryEntry   
> *entries,
>                                          gpointer               
> callback_data,
>                                          guint                  
> callback_type);
> 
> Each of these creation methods take a single callback_data
> element, which is passed to the appropriate callback (an
> attribute of each entry) on activate.  
> 
> In short, I'd really like to be able to set individual callback
> data elements for each entry, so that each menu item (in my
> case) can identify itself to the callback.  We're using a
> single, static callback handler as the callback for each 
> menu item (somewhat neccessary in C++), instead of writing
> multitudes of static callbacks for each menu item.  In fact,
> since we have run-time changable menus, this would be near
> impossible.

use gtk_item_factory_create_item() and its associated callback_data pointer.
if you use gtk_item_factory_create_items() all items get the same callback_data
pointer assigned, this is intentional behaviour since you'd usually do something
like:

void
gtk_item_factory_create_items (ifac,
                               sizeof (entries) / sizeof (entries[0]),
                               entries,
                               window);
with all entries having different callback_action values, e.g. from
an enum, so you can later:

enum {
  MY_APP_LOAD,
  MY_APP_SAVE,
  MY_APP_QUIT
};

static void
ifactory_callback (GtkWidget *window,
                   guint      callback_action,
                   GtkWidget *menu_item)
{
  switch (callback_action)
  {
    case MY_APP_LOAD:
    case MY_APP_SAVE:
    case MY_APP_QUIT:
  }
}
                   
                               
> 
> Shaw Terwilliger
> 

---
ciaoTJ