Question

I’ve set up a Singleton class. Several view controllers will be getting data from the singleton for their views. The data is periodically updated.

How would I set up the app so that the view controllers watch the singleton to see if there are changes in data… or the singleton sends a message to a view if there is new data relevant to that view?

Answer 1

You can use NSNotificationCenter to post notifications whenever the singleton’s data changes (such as setter methods) and have any associated views register to receive the notifications.

http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/nsnotificationcenter_Class/Reference/Reference.html