Create event listener bound to event source
el = addlistener(hSource,EventName,callback)
el = addlistener(hSource,PropertyName,EventName,callback)
hSource is an array, the listener responds to the named event on any
object in the
callback is a
function handle referencing the callback function.
|Event Name||Event Occurs|
Immediately before the property value is set, before calling its set access method
Immediately after the property value is set
Immediately before a property value query is serviced, before calling its get access method
Immediately after returning the property value to the query
hSource— Event source
Event source is the object that is source of the event, or an array of source objects, specified as a handle array.
EventName— Name of event
Name of event that is triggered on the source objects, specified as case-sensitive, quoted text. For property events, the event name is one of the four predefined property events.
PropertyName— Name of property
Name of the property whose property event triggers your listener, specified as one of these values:
A character vector or a cell array of character vectors, where
each character vector is the name of a property defined for the
An array of
You can attach listeners to property events on dynamic properties only
hSource is scalar. If
non-scalar, then the properties must belong to the class of
hSource and cannot include dynamic properties (which
are not part of the class definition).
The class defining the source property must set the
property attributes to enable you to listen to the property events.
callback— Listener callback
Listener callback specified as a function handle
el— Listener object
Listener object created by
addlistener, specified as
the handle to an
event.listener or an
Create a property listener for the
property of a graphics
fig = figure; propListener = addlistener(fig,'Color','PostSet',@(src,evnt)disp('Color changed'));
Set the value of the
Color property to
yellow. Setting the property triggers the
PostSet property event on the figure. The event
source object is the specific figure referenced by the handle
To remove a listener, delete the listener object returned by
addlistener. For example,
calls the handle class delete method to delete the object from the workspace and remove the listener.
Redefining or clearing the variable containing the handle of the listener (for
el) does not delete the listener. The event object
hSource) still has a reference to the
ties the listener's lifecycle to the object that is the source of the
To define a listener that is not tied to the event object, use the
event.listener constructor directly to create the
When you need the lifecycle of the listener object to be independent of the source object
handle.listener to create listeners.