Returns detailed change information for a fetch result.
- iOS 8.0+
- macOS 10.11+
- Mac Catalyst 13.0+
- tvOS 10.0+
- Xcode 8.0+
A Photos fetch result.
A change details object, or
nil if there have been no changes affecting the fetch result’s contents.
When Photos calls your change observer’s
photo method, call this
change method to get detailed change information about the results of a fetch you’ve previously performed. If there have been any changes in the Photos library affecting the fetch, the resulting
PHFetch object tells you if any contents in the fetch result have been added, removed, or changed since you fetched it. If there have been no changes since you performed the fetch, this method returns
Typically, if your app displays the members of a collection (such as an album or moment), you use a method such as
fetch to retrieve those members and then keep the resulting
PHFetch object. You can then pass that fetch result to this method to learn about changes to the collection, such as whether new members have been added to it (and which indexes to insert them at in your UI).
To find out about changes to an object’s properties, such as a collection’s title or an asset’s metadata, use the