On Jun 9, 2010, at 3:19 PM, Mazen M. Abdel-Rahman wrote: > I have a view class that observes changes in a model class's array via KVO. > Unfortunately - when ever the array is updated - the updates are sent to the > view one at at a time. > > In my model class I have the following line: > > NSMutableArray * eventsArrayProxy = [self > mutableArrayValueForKey:@"events"]; > [eventsArrayProxy addObjectsFromArray:appointments]; > > Which naturally causes the following method in my view class to be invoked: > > -(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object > change:(NSDictionary *)change context:(void *)context > > My problem is that observeValueForKeyPath.. is invoked once for each and > every single item in the appointments array (the array being added) - rather > than once for all of them. Is this standard behavior? And is there a way to > have it call observeValueForKeyPath.. one time for all the objects being > added? > > In my case - I am sometimes adding as much as a thousand or more objects - so > it is a severe performance issue right now. If this is the only way KVO > works for arrays then I will have to find another way around it - but I'm > hopeful perhaps there's some way this can be done.
You don't say how the "events" property is implemented in terms of accessor methods. Be sure to read these: <http://developer.apple.com/mac/library/documentation/cocoa/conceptual/KeyValueCoding/Concepts/AccessorConventions.html#//apple_ref/doc/uid/20002174-178830-BAJEDEFB> <http://developer.apple.com/mac/library/documentation/cocoa/conceptual/KeyValueCoding/Concepts/SearchImplementation.html#//apple_ref/doc/uid/20000955-SW2> <http://developer.apple.com/mac/library/documentation/cocoa/conceptual/KeyValueCoding/Concepts/Performance.html#//apple_ref/doc/uid/20002175-171187> Implementing the multiple-object variants of the mutating indexed accessor methods will almost certainly alleviate the problem. By the way, if you implement those indexed accessor methods, then you don't need to use -mutableArrayValueForKey:. You can just directly message "self" with the appropriate accessor. Regards, Ken _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
