from gi.repository import Gtk
import sys


class MyWindow(Gtk.ApplicationWindow):
    # a window

    def __init__(self, app):
        Gtk.Window.__init__(self, title="Switch Example", application=app)
        self.set_default_size(300, 100)
        self.set_border_width(10)

        # a switch
        switch = Gtk.Switch()
        # turned on by default
        switch.set_active(True)
        # connect the signal notify::active emitted by the switch
        # to the callback function activate_cb
        switch.connect("notify::active", self.activate_cb)

        # a label
        label = Gtk.Label()
        label.set_text("Title")

        # a grid to allocate the widgets
        grid = Gtk.Grid()
        grid.set_column_spacing(10)
        grid.attach(label, 0, 0, 1, 1)
        grid.attach(switch, 1, 0, 1, 1)

        # add the grid to the window
        self.add(grid)

    # Callback function. Since the signal is notify::active
    # we need the argument 'active'
    def activate_cb(self, button, active):
        # if the button (i.e. the switch) is active, set the title
        # of the window to "Switch Example"
        if button.get_active():
            self.set_title("Switch Example")
        # else, set it to "" (empty string)
        else:
            self.set_title("")


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):
        Gtk.Application.do_startup(self)

app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)