from gi.repository import Gtk

from gi.repository import Gio

import sys

class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):

        Gtk.Window.__init__(self, title="GMenu Example", application=app)

class MyApplication(Gtk.Application):

    def __init__(self):

        Gtk.Application.__init__(self)

    def do_activate(self):

        win = MyWindow(self)

        win.show_all()

    def do_startup(self):

        # start the application

        Gtk.Application.do_startup(self)

        # create a menu

        menu = Gio.Menu()

        # append to the menu three options

        menu.append("New", "app.new")

        menu.append("About", "app.about")

        menu.append("Quit", "app.quit")

        # set the menu as menu of the application

        self.set_app_menu(menu)

        # create an action for the option "new" of the menu

        new_action = Gio.SimpleAction.new("new", None)

        # connect it to the callback function new_cb

        new_action.connect("activate", self.new_cb)

        # add the action to the application

        self.add_action(new_action)

        # option "about"

        about_action = Gio.SimpleAction.new("about", None)

        about_action.connect("activate", self.about_cb)

        self.add_action(about_action)

        # option "quit"

        quit_action = Gio.SimpleAction.new("quit", None)

        quit_action.connect("activate", self.quit_cb)

        self.add_action(quit_action)

    # callback function for "new"

    def new_cb(self, action, parameter):

        print("This does nothing. It is only a demonstration.")

    # callback function for "about"

    def about_cb(self, action, parameter):

        print("No AboutDialog for you. This is only a demonstration.")

    # callback function for "quit"

    def quit_cb(self, action, parameter):

        print("You have quit.")

        self.quit()

app = MyApplication()

exit_status = app.run(sys.argv)

sys.exit(exit_status)