There are times when building an iPhone application that you
need to inform other parts of the program to do something, without regard to
what or where those parts are. The NSNotificationCenter (aka “notification
center”) is the way to go in these cases. Using notifications supports ‘loose
coupling’, which is a good thing in software design.
A notification center object provides a mechanism for
broadcasting information (“notifications”) within a task. An
NSNotificationCenter object is basically a notification dispatch table. For
those familiar with Windows programming, this pattern is similar to the Windows
Message Loop architecture.