The starting point

Our "Hello, Kivy" example from the preface is a suitable starting point for this app. We just need to add a layout container, BoxLayout, so that we can fit more than one widget on the screen later.

This is the full source code at this point:

# File: main.py
from kivy.app import App

class ClockApp(App):
    pass

if __name__ == '__main__':
    ClockApp().run()

# File: clock.kv
BoxLayout:
    orientation: 'vertical'

    Label:
        text: '00:00:00'

Right now, it looks and behaves exactly like the previously seen "Hello, world" app. A BoxLayout container allows two or more child widgets to coexist side by side, stacking either vertically or horizontally. Given just one nested widget, as in the preceding code, BoxLayout fills up all the available screen space with it and thus becomes practically unnoticeable (it's as if Label was a root widget instead, taking over the application window). We will review layouts in more detail later on.