NSNotificationCenter — Mac OS X 10.0
This class is the core of Cocoa’s
register with the default
notification center to receive notifications posted by other objects.
The default notification center, which is also used for system
notifications, is obtained using the class method
register an object as a receiver of a specified
notification, we use the method
addObserver:selector:name:object:. The observer is
the object that wishes to be notified of the notification identified
argument is the selector for the method to be invoked in
parameter allows us to restrict the notifications to which the
observer responds to those posted by the specified object. To remove
an observer we invoke the method
which removes the observer for all notifications. If we want to be
selective about what notifications from which objects we wish to stop
observing, we can use the method
NSNotificationCenter provides three methods for
postNotificationName:object:userInfo:. Each of
these methods offers different levels of control over how the
notification is posted.
For more information about the notifications system, see Chapter 2.
@interface NSNotificationCenter : NSObject
// Class ...