Comments on: Getting started with Key-Value Observing

By: Corey

Corey — Fri, 13 Aug 2010 15:37:29 +0000

Actually you can google MAKVONotificationCenter, where Mike Ash has done just that. I use it myself and does make for cleaner code!

By: Terry

Terry — Fri, 13 Aug 2010 07:34:06 +0000

Thanks. Your explanation of KVO has made the MVC idea clearer for me. KVO should be more prominent in all the various iPhone programming books out there, if only to give people a tool to make apps more MVC complient.

…on the other hand, it does seem that Apple could have a cleaner approach to implementing KVO in Objective-C. The current approach requires a lot of if statements (if keyPath isEqual..etc) in the observeValueForKeyPath method, if several keyPaths are being observed.
A better implementation might be:
[obj addObsever:self forKeyPath:@"person.name" usingSelector:@selector(nameChanged:)]
So a separate method is fired directly when the keyPath’s value is changed.

By: Corey

Corey — Thu, 12 Aug 2010 22:54:48 +0000

That is a pretty typical use case. Since there are no bindings on the iPhone, however, you have to still need some “glue code” in your view controllers.

Also, you do not want the model to observe the view, that makes it less portable. Your controllers should update the model directly.

By: Terry

Terry — Thu, 12 Aug 2010 21:55:00 +0000

Can KVO be used as the glue between the Model and View? So the Controller, using KVO, observes changes in the Model and updates the View, and vice versa?

By: Corey

Corey — Sat, 20 Jun 2009 01:37:21 +0000

i got it from @dtm3dd. Check his blog post or his past tweets, I think it was called seaside or something similar.

By: Uprise78

Uprise78 — Fri, 19 Jun 2009 17:32:41 +0000

Totally off topic…where did you get the Xcode theme and would you mind sharing it?

By: iPhoneKicks.com

iPhoneKicks.com — Fri, 05 Jun 2009 10:20:15 +0000

Getting started with Key-Value Observing …

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