MATLAB Object-Oriented Programming

• @RespondToToggle.handleEvnt — A function handle to the callback function (see
  the following definition “Define Listener” on page 11-24).

Use handle.listener to Decouple Listener and Source

Use the handle.listener method to create listeners when you want to manage the

lifecycle of the listener and do not want a coupling between the event source and listener

object. MATLAB does not destroy listeners created with handle.listener when the

event source is destroyed. However, your code must keep the listener object handle in

scope when creating listeners using handle.listener.

The handle.listener method requires the same arguments as handle.addlistener:

the event-naming object, the event name, and a function handle to the callback.

handle.listener returns the handle to the listener object.

lh = listener(obj,'EventName',@callbackFunction)

For example, this code uses the ToggleState event discussed previously:

lh = listener(obj,'ToggleState',@RespondToToggle.handleEvnt)

Callback Function

The listener callback function must accept a minimum of two arguments, which MATLAB

automatically passes to the callback. Here are the required arguments:

• The source of the event — that is, obj in the call to addlistener or
  event.listener.


• An event.EventData object or a subclass of event.EventData, such as the
  ToggleEventData object described in, “Define Event-Specific Data” on page 11-26.

Define the callback function to accept the source object and event data arguments.

function callbackFunction(src,evtdata)

...

end

For more information on callback syntax, see “Listener Callback Syntax” on page 11-30.

Define Listener

The RespondToToggle class defines objects that listen for the ToggleState event

defined in the ToggleButton class.

11 Events — Sending and Responding to Messages