An advanced interface for managing a data source object.
- iOS 11.0+
- tvOS 11.0+
Use the methods of this protocol to map between the positions of items and sections in your data source object and the positions of those same items and sections in your presented layout. Objects that adopt this protocol do so because the position of items in their data source object do not always match the corresponding positions in their presented layout.
UICollection adopt this protocol and use it in conjunction with drag and drop operations. For example,
UITable must account for the presence of placeholder cells, which appear as rows in the table but do not have a corresponding entry in the data source object. Typically, you do not adopt this protocol in your own classes.