from kivy.app import App
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.widget import Widget
from kivy.uix.screenmanager import ScreenManager, Screen


class myGrid(Widget):
    pass

kv = Builder.load_file("my.kv")


class mainWindow(Screen):
    pass

class secondWindow(Screen):
    pass




screen_manager = ScreenManager()
screen_manager.add_widget(mainWindow())
screen_manager.add_widget(secondWindow())
screen_manager.current = "main"



class myApp(App):
    def build(self):
        return screen_manager





if __name__ == "__main__":
    myApp().run()