NSCollectionViewElement
A set of methods that you use to manage the content in a collection view.
Declaration
protocol NSCollectionViewElement : NSUserInterfaceItemIdentification, NSObjectProtocolOverview
Adopt this protocol in the classes that you use to display content for items, supplementary views, and decoration views in a collection view. The methods of this protocol are optional and provide support for applying layout attributes and for cleaning up elements when they move offscreen and are recycled.
Collection view items—that is, instances of the NSCollectionViewItem class—already adopt this protocol. For supplementary and decoration views, adopt this protocol in the custom view classes you use to represent that content.