fingerprintscanner.kv

#:kivy 1.9.1
<MenuScreen>:

    BoxLayout:
        orientation: 'vertical'

        Label:
            text: 'Fingerprint Scanner'
            font_size: 24

        GridLayout:
            size: root.size
            rows: 2
            cols: 2
            spacing: 10
            padding: 10

            Button:
                text: 'Login'
                size_hint_y: None
                on_press: root.manager.current = 'login'

            Button:
                text: 'Register'
                size_hint_y: None

            Button:
                text: 'Check Compatibility'
                size_hint_y: None
                on_press: root.manager.current = 'compatibility'

            Button:
                text: 'Quit'
                size_hint_y: None
                on_press: app.stop()

<LoginScreen>:
    BoxLayout:
        Button:
            text: 'My login button'
        Button:
            text: 'Back to main menu'
            on_press: root.manager.current = 'menu'

<CompatibilityScreen>:
    BoxLayout:
        Button:
            text: 'Check if device is compatible'
        Button:
            text: 'Back to main menu'
            on_press: root.manager.current = 'menu'