invalidateDecorationElements(ofKind:at:)
Marks the specified decoration views as invalid so that their layout information can be updated.
Declaration
func invalidateDecorationElements(ofKind elementKind: NSCollectionView.DecorationElementKind, at indexPaths: Set<IndexPath>)Parameters
- elementKind:
A string that identifies the type of the decoration views. This parameter must not be
nilor an empty string. - indexPaths:
A set of Nsindexpath objects. Each index path contains the section in which the decoration view appears.
Discussion
Call this method when you want the layout object to recompute attributes for one or more decoration views. All of the views must be of the type specified by the elementKind parameter. The method adds the views you specify to the invalidatedDecorationIndexPaths property. You can call this method more than once for the specified elementKind value.