On 16 Nov 2012, at 22:00, Rick Mann <rm...@latencyzero.com> wrote:

> 
> On Nov 16, 2012, at 2:31 , Mike Abdullah <cocoa...@mikeabdullah.net> wrote:
> 
>> Why are you trying to avoid "a bunch of" these calls? Is it just to save 
>> yourself typing?
> 
> Typing, and code maintenance. I generally have UI that displays all (or some 
> subset of) the properties of one of my entities. I'd like that UI to update 
> if anything updates one of the models. But if there are a dozen properties, 
> then that's a dozen -addObserver and -removeObserver calls, in each place 
> where there might be UI associated with it. If I later add a new property to 
> the entity, I have to be sure to KVO, it, too. If I remove a bit of the UI, I 
> have to remember to remove the call (not strictly, but I like keeping my code 
> clean).
> 
> Being able to subscribe once for all changes to a single object makes these 
> problems go away.

This is Core Data. You have all the information available to you automatically:

NSEntity *entity = [someManagedObject entity];
for (NSPropertyDescription *aProperty in [entity properties])
{
    [someManagedObject addObserver:self forKeyPath:[aProperty name] …
}

Obviously you can adjust that snippet to focus on just attributes, or skip some 
out, as desired.


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