
396 9 Chapter 19: Making It Happen: Events, Responders, Delegates, and Notification
Delegates
provide a way for an application and its objects to pass
events along to other interested objects.
The
notification
system in Cocoa does just what its name implies:
It allows one object to automatically notify others (which it may not
even know about) when something has happened.
Note that a number of the concepts in this chapter are required to im-
plement toolbars. The complete code for implementing toolbars is
given in Chapter 20; see "Implementing Toolbars" on page 440.
Events
Types of Events
In all graphical user interface frameworks, ...