MATLAB Object-Oriented Programming

Events and Listeners

In this section...

“Define and Trigger Events” on page 5-20

“Listen for Events” on page 5-20

Define and Trigger Events

To define an event, declare a name for the event in an events block. Trigger the event

using the handle class notify method. Only classes derived from the handle class can

define events.

For example, MyClass class:

• Subclasses handle


• Defines an event named StateChange


• Triggers the event using the inherited notify method in its upDateUI method.

classdef MyClass < handle

events

StateChange

end

...

methods

function upDateUI(obj)

...

notify(obj,'StateChange');

end

end

end

Listen for Events

Any number of objects can listen to the StateChange event. When notify executes,

MATLAB calls all registered listener callbacks. MATLAB passes the handle of the object

generating the event and event data to the callback functions. To create a listener, use the

addlistener method of the handle class.

addlistener(event_obj,'StateChange',@myCallback)

To control the lifecycle of the listener, use the event.listener constructor to create the

listener object.

5 Class Definition—Syntax Reference