Kivy is mostly event-based, meaning the flow of the program is determined by events.
The Clock object allows you to schedule a function call in the
future as a one-time event with
or as a repetitive event with
You can also create Triggered events with
create_trigger(). Triggers have the advantage of
being called only once per frame, even if you have scheduled multiple triggers
for the same callback.
All the mouse click, touch and scroll wheel events are part of the
MotionEvent, extended by
Input Postprocessing and dispatched through the
on_motion event in
Window class. This event then generates the
on_touch_up() events in the
For an in-depth explanation, have a look at Input management.
Our base class
EventDispatcher, used by
Widget, uses the power of our
Properties for dispatching changes. This means when a widget
changes its position or size, the corresponding event is automatically fired.
Another thing to note is that if you override an event, you become responsible for implementing all its behaviour previously handled by the base class. The easiest way to do this is to call super():
def on_touch_down(self, touch):
if not self.collide_point(touch.x, touch.y):
print('you touched me!')
Get more familiar with events by reading the Events and Properties documentation.