How do you check for keyboard events with kivy?

I guess you are asking how to control the paddles with the keyboard. I assume you have the final ping pong codes running on your computer (If not, you can find them at the end of this section).

1 – In the main.py import the Window class:

from kivy.core.window import Window

2 – Redefine the beginning of the PongGame class so it looks like the following:

class PongGame(Widget):
    ball = ObjectProperty(None)
    player1 = ObjectProperty(None)
    player2 = ObjectProperty(None)

    def __init__(self, **kwargs):
        super(PongGame, self).__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):
        if keycode[1] == 'w':
            self.player1.center_y += 10
        elif keycode[1] == 's':
            self.player1.center_y -= 10
        elif keycode[1] == 'up':
            self.player2.center_y += 10
        elif keycode[1] == 'down':
            self.player2.center_y -= 10
        return True

Voilà! Press w and s for the left paddle and up and down for the right paddle.