I usually design GUI with Glade, thus producing a series of Builder XML files (one such file for each application window).

Now my idea is to define a class, e.g. MainWindow, that inherits from gtk.Window and that implements all the signal handlers for the application main window. The problem is that when I retrieve the main window from the containing XML file, it is returned as a gtk.Window instance.

The solution I have adopted so far is the following:

I have defined a class "Window" in the following way

class Window():
def __init__(self, win_name):
    builder = gtk.Builder()
    self.builder = builder
    builder.add_from_file("%s.glade" % win_name)
    self.window = builder.get_object(win_name)
    builder.connect_signals(self)

def run(self):
    return self.window.run()

def show_all(self):
    return self.window.show_all()

def destroy(self):
    return self.window.destroy()

def child(self, name):
    return self.builder.get_object(name)

In the actual application code I have then defined a new class, say MainWindow, that inherits frow Window, and that looks like

class Main(Window):
def __init__(self):
    Window.__init__(self, "main")

### Signal handlers #####################################################

def on_mnu_file_quit_activated(self, widget, data = None):
    ...

The string "main" refers to the main window, called "main", which resides into the XML Builder file "main.glade" (this is a sort of convention I decided to adopt).

So the question is: how can I inherit from gtk.Window directly, by defining, say, the class Foo(gtk.Window), and recast the return value of builder.get_object(win_name) to Foo?