kv 23 login screen

#screen2.py

from kivy.app import App

from kivy.uix.screenmanager import ScreenManager, Screen

from kivy.lang import Builder

class MainWindow(Screen):

    pass

class SecondWindow(Screen):

    pass

class WindowManager(ScreenManager):

    pass

kv = Builder.load_file("screen2.kv")

class Screen2App(App):

    def build(self):

        return kv

Screen2App().run()

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

#screen2.kv

WindowManager:

    MainWindow:

    SecondWindow:

<MainWindow>:

    name: "main"

    GridLayout:

        size_hint: 1, 0.5

        pos_hint: {"y": 0.25}

        cols:1

        GridLayout:

            cols: 2

            Label:

                text: "Password: "

            TextInput:

                id: passw

                multiline: False

                padding : 6,self.height/2 - self.font_size/2,6,6

        Button:

            text: "submit"

            on_release: app.root.current = "second" if passw.text == "password" else "main"

<SecondWindow>:

    name: "second"

    Button:

        size_hint: 0.5, 0.5

        pos_hint: {"x": 0.25, "y": 0.25}

        text: "Go Back"

        on_release: app.root.current = "main"

reference:

https://www.youtube.com/watch?v=xaYn4XdieCs