Specifically detailing what defaults have changed on NSUserDefaultsDidChangeNotification

Question

I\'m starting to get into the inner sanctum of NSUserDefaults to the point where I can now successfully intercept an NSUserDefaultsDidChangeNotification notification using a sup

Answer 1

Take a look at Apple's documentation: http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSUserDefaults_Class/Reference/Reference.html

At the very end there is a notifications section which states:

NSUserDefaultsDidChangeNotification This notification is posted when a change is made to defaults in a persistent domain. The notification object is the NSUserDefaults object. This notification does not contain a userInfo dictionary.

So the NIL userInfo dictionary is a choice Apple made. If you really want this feature I would recommend you submit a comment to Apple via http://bugreport.apple.com/

I ultimately got around this by just writing some logic to compare the settings in the notification to the ones I had loaded to let me know which ones had changed.

Answer 2

you can use KVO (Key Value Coding) to track specific keys in the NSUserDefaults. See my answer here with code snippets: https://stackoverflow.com/a/10950217/388412

Instead of registering as a general observer for any NSUserDefaultsDidChangeNotifications in the NSNotificationCenter, you can register to observe key-value-changes for a specific key of the NSUserDefaults standardUserDefaults object.