Performs needed tasks before items are inserted, deleted, or moved within the collection view.
- macOS 10.11+
An array of
NSCollectionobjects that identify the changes being made.
View Update Item
When items are inserted, deleted, or moved, the collection view calls this method to report those changes to the layout object. The default implementation uses the provided information to plan the layout animations needed to respond to the changes. Subclasses can override this method and use it to prepare for any custom changes, but you should always call
super at some point in your implementation.