kv35 menu

#menu.py

from kivy.app import App

from kivy.uix.widget import Widget

class Menu(Widget):

    def toggle1(self, widget):

        widget.background_color = [0, 1, 1, 1]

        self.ids["button2"].background_color = [1, 1, 1, 1]

        self.ids["button3"].background_color = [1, 1, 1, 1]

        self.ids["screen_manager"].current = "window1"

    def toggle2(self, widget):

        widget.background_color = [0, 1, 1, 1]

        self.ids["button1"].background_color = [1, 1, 1, 1]

        self.ids["button3"].background_color = [1, 1, 1, 1]

        self.ids["screen_manager"].current = "window2"

    def toggle3(self, widget):

        widget.background_color = [0, 1, 1, 1]

        self.ids["button1"].background_color = [1, 1, 1, 1]

        self.ids["button2"].background_color = [1, 1, 1, 1]

        self.ids["screen_manager"].current = "window3"

class MenuApp(App):

    pass

MenuApp().run()

-----------------------------

#menu.kv

Menu:

    BoxLayout:

        size: root.width, root.height

        orientation: "vertical"

        BoxLayout:

            size_hint: 1, 0.2

            Button:

                id: button1

                text: "1"

                on_press: root.toggle1(self)

            Button:

                id: button2

                text: "2"

                on_press: root.toggle2(self)

            Button:

                id: button3

                text: "3"

                on_press: root.toggle3(self)

        ScreenManager:

            id: screen_manager

            Window1:

            Window2:

            Window3:

<Window1@Screen>:

    name: "window1"

    Label:

        text: "window 1"

        font_size: "150dp"

<Window2@Screen>:

    name: "window2"

    Label:

        text: "window 2"

        font_size: "150dp"

<Window3@Screen>:

    name: "window3"

    Label:

        text: "window 3"

        font_size: "150dp"