Creating your own events – the magical properties

This section covers the use of Kivy properties. A Kivy property triggers an event every time we modify it. There are different types of properties, from the simple NumericProperty or StringProperty to much more complex versions like ListProperty, DictProperty, or ObjectProperty. For example, if we define a StringProperty, called text, then an on_text event is going to be triggered each time text is modified.

Note

The on_translation method (line 243) is associated with the ListProperty in line 216 called translation. Once we define a Kivy property, Kivy internally creates an event associated with that property. The property name is generated adding the prefi x on_ to the name of the property.

All the properties work in the same way. For example, the state property of ToogleButton is actually a property which creates the on_state event. We alreadsed this event in line 203. We define the property and Kivy creates the event for us.

Note

In the context...