I have something like this:
A. UICollectionView1 with FRC1 and FRC_Search_1 for UICollectionView_Search_Results_1
B. UICollectionView1 with FRC2 and FRC_Search_2 for UICollectionView_Search_Results_2
C. UICollectionView1 with FRC3 and FRC_Search_3 for UICollectionView_Search_Results_3
D. UICollectionView1 with FRC4 and FRC_Search_4 for UICollectionView_Search_Results_4
.
.
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Idea was to use NSFetchedResultsControllerDelegate for updating Collection Views. But if I implement it at both A and B, after one update, both implementation will be called. I don't understand why is this happening. Is it because both FRCs are pulling from same entity or because they have same context or something else?
What is the best approach to solve this?
EDIT:
@Tuslareb
I have 2 UICollectionViewControllers with seperate classes. Each has it's own FRC, collectionView and Delegate implementation. If FRCs looks the same ( same entity,predicate...) both delegates are activated when I update only one collectionView in one collectionViewController.
Problem occurs if those 2 collectionViews are different. Then indexPaths are different, and updating produces errors and stops app.
This is probably the way it works, core data is observing type of FRC but not objects itself. But I wanted to be sure.
When a delegate is set for a FRC, the FRC will receive change notifications from the context. Then, the FRC will notify the delegate whose methods will update the collection (or table) view. So, as you already did find out yourself, any changes in the context will notify the FRC delegate when the FRC object is 'alive'.
This answers at least one part of your question. To solve it, you will need to obtain a reference to the collection view that was changed and change the delegate methods in a way that they will only be executed for the view that was changed.