Как мне вызвать выпадающее меню из моего файла main.py

Question

Я пишу небольшую игру на Kivy, Python, и я создал выпадающее меню, я очень плохо знаком с kivy и не уверен, как запускать код выпадающего меню каждый раз, когда загружаюновый экран, так что у меня есть возможность перейти в это меню, независимо от того, на каком экране я могу быть.

Я уже искал ответ в Google и не могу найти ничего!

Файл Main.py!

import kivy
from kivy.app import App
from kivy.uix.image import Image
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.core.image import Image as CoreImage
from kivy.properties import ObjectProperty
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.window import Window
from kivy.uix.dropdown import DropDown
from kivy.config import Config

Все классы здесь

Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class CustomDropDown(BoxLayout):
    pass

class RootScreen(ScreenManager):
    pass

class MyScreenManager(ScreenManager):
    pass

class Game(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)
        Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class Game2(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)
        Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class Game3(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)
        Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class Game4(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)
        Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class Game5(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)
        Window.clearcolor = (0.50, 0.50, 0.50, 0.50)

class Title(Screen):
    def on_pre_enter(self):
        Window.size = (800, 600)

    def closewindow(self):
        Window.close()

class MyWindow(App):
    def build(self):
        self.title = "TheAvengersGame"
        return MyScreenManager()
        return RootWidget()
        return CustomDropDown()


window = MyWindow()
window.run()

Файл mywindow.kv!

<MyScreenManager>:
    Title:
    Game:
    Game2:
    Game3:
    Game4:
    Game5:

Все экраны .kv

<Title>:
    name: "Title"
    FloatLayout:
        Label:
            text: "Avengers Assemble"
            pos_hint: {"x": .3, "y": .7}
            size_hint: .4, .2
            font_size: "50dp"

        Button:
            id: PlayButton
            text: "Play!"
            pos_hint: {"x": .3, "y": .4}
            size_hint: .4, .1
            on_press:
                root.manager.current = "main"

        Button:
            id: QuitButton
            text: "Quit!"
            pos_hint: {"x": .3, "y": .2}
            size_hint: .4, .1
            on_press:
                root.closewindow()



<Game2>:
    name: "Avengers Tower"
    FloatLayout:
        Label:
            text: "You are in the Avengers Tower!"
            pos_hint: {"x": .45, "y": .6}
            font_size: "20dp"
            size_hint: None, None

        Button:
            text: "North"
            pos_hint: {"x": .45, "y": .85}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "AvengersCourtyard"

<Game3>:
    name: "AvengersCourtyard"
    FloatLayout:
        Label:
            text: "You are in the Avengers Courtyard!"
            font_size: "20dp"
            pos_hint: {"x": .45, "y": .6}
            size_hint: None, None

        Button:
            text: "North"
            pos_hint: {"x": .45, "y": .85}
            height: 50
            size_hint: None, None
            on_press:
                root.manager.current = "ChinaTown"

        Button:
            text: "East"
            pos_hint: {"x": .8, "y": .4}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "Apartments"

        Button:
            text: "South"
            pos_hint: {"x": .45, "y": .05}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "Avengers Tower"


<Game4>:
    name: "Apartments"
    FloatLayout:
        Label:
            text: "You are in the Apartments!"
            pos_hint: {"x": .45, "y": .6}
            font_size: "20dp"
            size_hint: None, None

        Button:
            text: "West"
            pos_hint: {"x": .05, "y": .45}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "AvengersCourtyard"



<Game5>:
    name: "ChinaTown"
    FloatLayout:
        Label:
            text: "You are in China Town!"
            pos_hint: {"x": .45, "y": .6}
            font_size: "20dp"
            size_hint: None, None

        Button:
            text: "South"
            pos_hint: {"x": .45, "y": .05}
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "AvengersCourtyard"



<Game>:
    name: "main"
    FloatLayout:
        Button:
            text: "<- Back"
            font_size: "15dp"
            pos: 40, 510
            size_hint: None, None
            height: 50
            on_press:
                root.manager.current = "Title"

        Label:
            text: "Choose a character!"
            font_size: "50dp"
            pos_hint: {"x": .3, "y": .7}
            size_hint: .4, .2

        ToggleButton:
            text: "Iron Man"
            font_size: "15dp"
            pos: 200, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Iron Man"

        ToggleButton:
            text: "Thor"
            font_size: "15dp"
            pos: 350, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Thor"

        ToggleButton:
            text: "Scarlett Witch"
            font_size: "15dp"
            pos: 500, 150
            size_hint: None, None
            height: 80
            group: "character"
            on_press:
                char = "Scarlett Witch"

        Button:
            text: "Play!"
            height: 50
            font_size: "15dp"
            pos: 650, 60
            size_hint: None, None
            on_press:
                root.manager.current = "Avengers Tower"

<CustomDropDown>:
    Button:
        id: btn
        text: 'Press'
        on_release: dropdown.open(self)
        on_parent: dropdown.dismiss()
        size_hint_y: None
        height: '48dp'

    DropDown:

        id: dropdown
        on_select: btn.text = '{}'.format(args[1])

        Button:
            text: 'First Item'
            size_hint_y: None
            height: '48dp'
            on_release: dropdown.select('First Item')

        Button:
            text: 'Second Item'
            size_hint_y: None
            height: '48dp'
            on_release: dropdown.select('Second item')

        Button:
            text: 'Third Item'
            size_hint_y: None
            height: '48dp'
            on_release: dropdown.select('Third Item')

Раскрывающееся меню не создается вообще.Я знаю это, поскольку я не призывал его поставить на экран.