Cocoa Programming for OS X: The Big Nerd Ranch Guide

NSNotificationCenter

The NSNotificationCenter is the brains of the operation. It allows you to do three things: register observer objects, post notifications, and unregister observers.

Here are some commonly used methods implemented by NSNotificationCenter:

c​l​a​s​s​ ​f​u​n​c​ ​d​e​f​a​u​l​t​C​e​n​t​e​r​(​)​ ​-​>​ ​N​S​N​o​t​i​f​i​c​a​t​i​o​n​C​e​n​t​e​r​

Returns the notification center.

f​u​n​c​ ​a​d​d​O​b​s​e​r​v​e​r​(​o​b​s​e​r​v​e​r​:​ ​A​n​y​O​b​j​e​c​t​,​
 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​s​e​l​e​c​t​o​r​ ​a​S​e​l​e​c​t​o​r​:​ ​S​e​l​e​c​t​o​r​,​
 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​n​a​m​e​ ​a​N​a​m​e​:​ ​S​t​r​i​n​g​?​,​
 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​o​b​j​e​c​t​ ​a​n​O​b​j​e​c​t​:​ ​A​n​y​O​b​j​e​c​t​?​)​