The Kivy .kv Language

While you can get by writing Kivy applications without ever writing Kivy language (.kv), using the Kivy language may be useful to you for organization and separating application logic from the presentation of it.

It may also boil down to preference in the end. Try both and see what you like best.

Here, we're going to show a very basic implementation of the Kivy language.

KivyVideo3.py file:

from kivy.app import App
#kivy.require("1.8.0")
from kivy.uix.label import Label


class SimpleKivy(App):
    def build(self):
        return Label()

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

So now, let's make the kivy file, calling it SimpleKivy.kv:

#:kivy 1.8.0

<Label>
    text: 'Hello'+' World!'
		

You could also say text: "Hello world!" I chose to show that you can include some basic Python code as well within the Kivy files.

This is just a basic example, showing the same result as the previous tutorial. The main advantage by using the Kivy language is just for organization. If you have, say, 50 labels in total, 20 buttons, and various other widgets, it will clutter your Python script quite a bit to do all of the styling within it. It might just help for clarity alone to separate the two. Kivy language reminds me a lot of CSS, or stylesheets, for HTML. While you could write all of your styles in line with your HTML, it just makes more sense to separate it.

The next tutorial: Kivy .kv Language cont'd