from kivy.app import App
from kivy.lang import Builder
from kivy.core.window import Window
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.uix.textinput import TextInput

kv = '''ScreenManagement:
    MainScreen:

<MainScreen>:
    name: "main"
    BoxLayout:
        Label:
            text: "Label"
            font_size: 20
            size_hint: 0.2,0.1
        TextInput
            input_filter: 'float'
            font_size: 20
            hint_text: "Input Text"
            size_hint: 0.2,0.1'''

class MainScreen(Screen):

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def _keyboard_closed(self):
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        print('INFO: The key', keycode, 'has been pressed')

        return True # return True to accept the key. Otherwise, it will be used by the system.

class ScreenManagement(ScreenManager):
    pass

class MainApp(App):
    def build(self):
        return Builder.load_string(kv)

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