How can I set KVO (key-value-observing) with an NSMutableArray?
I want to be notified when a change appears in the array. I never used KVO before with a collection like an array.
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I think you’ll be interested in the answers to this question.
The key is that you can’t observe any properties on the array directly—the array is just storage—but you can observe the to-many relationship that’s backed by that array (here I’m assuming your array is a property on an object somewhere).
If you don’t want to use those special accessors all over the place, your code that owns the array can call
-willChange:valuesAtIndexes:forKey:and-didChange:valuesAtIndexes:forKey:as described in this answer.
And if you’re on a Mac and not iOS, you should consider
NSArrayController.