CODEWITHSUNDEEP
iphoneios5nsnotificationcenter
Doug
Doug

Reputation: 869

NSNotification observer Overhead

Just wondering, does anyone have experience with activating large amounts of NSNotification observers at a time?

What is the overhead of an observer? Is it reasonable to run, say, 50 or 100 or more observers at a time?

I have an application that displays a scrolling list of media from database and I want to implement NSNotificationCenter as a scalable method of listening for individual pieces of media and allocating them to the proper UIViews

Cheers, Doug

Upvotes: 1

Views: 246

Answers (2)

Doug
Doug

Reputation: 869

I'm going to take J2theC's advice on this one..

I'm currently shifting the design pattern to use delegate methods to prevent any freezing..

Thanks for the feedback!

Upvotes: 0

Kunal Balani
Kunal Balani

Reputation: 4789

Notification does not have overheads if they are processed in background. If you process NSNotification in one single thread then any one of the observers can mishandle it which would lead to a blocking thread. If this thread happens to be the main thread (in your case it is ) then app will freeze .

It depends upon the way notification is handled. Sending notification is not an overhead they are just 50 -100 method calls just like any other methods. (I have 5000 methods in my app). The issue is thw way it is handled. If each observer blocks the notification for a long time then nothing can be done. I will suggest using NSNotification queues instead NSNotification Queue

If time permits I would also suggest to refer reading article on Objects Communication by apple.

Upvotes: 1

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