How to use glade with a GtkHeaderBar with different layouts

[Iñigo Martínez <inigomartinez gmail com>]

Recently, I started moving UI code from bare C to Glade XML files, so
the UI definition gets split from the UI logic.

One of the widgets I have been moving is a GtkHeaderBar. The
application uses a GtkStack to move between diferent windows, and the
code creates, adds and destroys the buttons on the header everytime it
moves through those window states. All is done in the same class,
derived from GtkHeaderBar.

The first challenge here is that, as far as I know, I can only
init/load one template per class. This solves only part of the
problem, as I can create a template file for the most used/common
window state, and create and change the buttons while they change,
although I feel that I'm not taking any of the advantages from Glade.
Here goes my first question: Is there any possibility of using more
than one template on the same class?

I have been looking at some GNOME applications code, and none of them
do this, so I think that its probably not possible. I've been thinking
about other approaches, but I don't know what could be the proper one,
or even if I could be doing some weird things.

One approach could be to define all the possible widgets/buttons of
the header in the template file. They would be created but I should
add and remove them continuously which doesn't look very
efficient/clean.

Another approach would be to create different classes for every
possible header, each with their different template file, loading them
on every window state and adding and removing the full header to/from
the window. The idea is similar to what GtkStack does with windows,
but applied to headers.

Is there any reasonable answer for this or has anyone encountered a
similar problem?

Best regards,