add_callback¶
- echo.add_callback(instance, prop, callback, echo_old=False, priority=0)[source]¶
Attach a callback function to a property in an instance
- Parameters
- instance
The instance to add the callback to
- propstr
Name of callback property in instance
- callbackfunc
The callback function to add
- echo_oldbool, optional
If True, the callback function will be invoked with both the old and new values of the property, as
func(old, new)
. If False (the default), will be invoked asfunc(new)
- priorityint, optional
This can optionally be used to force a certain order of execution of callbacks (larger values indicate a higher priority).
Examples
class Foo: bar = CallbackProperty(0) def callback(value): pass f = Foo() add_callback(f, 'bar', callback)