PHObjectChangeDetails
A description of changes that occurred in an asset or collection object.
Declaration
class PHObjectChangeDetails<ObjectType> where ObjectType : PHObjectOverview
A PHObjectChangeDetails object provides detailed information about differences between two states of an asset or collection object—one that you previously obtained and an updated state that would result if you fetched that entity again. You observe changes by adopting the PHPhotoLibraryChangeObserver protocol and registering your observer with the shared PHPhotoLibrary object. When Photos notifies your observer of a change, you get change details by passing the object you’re interested in to the changeDetailsForObject: method.
For an asset collection or collection list, a PHObjectChangeDetails object describe changes only to the collection’s properties. If you’re instead interested in changes to the collection’s membership, fetch the collection’s contents and use the changeDetails(for:) method to track changes to the fetch result.