MATLAB Object-Oriented Programming

Overview Events and Listeners

In this section...

“Why Use Events and Listeners” on page 11-2

“Events and Listeners Basics” on page 11-2

“Events and Listeners Syntax” on page 11-3

“Create Listener” on page 11-4

Why Use Events and Listeners

Events are notices that objects broadcast in response to something that happens, such as

a property value changing or a user interaction with an application program. Listeners

execute functions when notified that the event of interest occurs. Use events to

communicate changes to objects. Listeners respond by executing the callback function.

For more information, see “Event and Listener Concepts” on page 11-14.

Events and Listeners Basics

When using events and listeners:

• Only handle classes can define events and listeners.


• Define event names in the events block of a class definition (“Events and Listeners
  Syntax” on page 11-22).


• Use event attributes to specify access to the event (“Event Attributes” on page 11-
  19).


• Call the handle handle.notify method to trigger the event. The event notification
  broadcasts the named event to all listeners registered for this event.


• Use the handle handle.addlistener method to couple a listener to the event source
  object. MATLAB destroys the listener when the source of the event is destroyed.


• Use the handle handle.listener method to create listeners that are not coupled to
  the lifecycle of the event source object. This approach is useful when the event source
  and the listeners are defined in different components that you want to be able to add,
  remove, or modify independently. Your application code controls the listener object
  lifecycle.

11 Events — Sending and Responding to Messages