A Boolean that indicates that all layout data should be marked as invalid.
- iOS 7.0+
- tvOS 9.0+
You do not set this property yourself. The collection view sets it in response to specific types of layout invalidation scenarios. For example, the collection view sets it to
true when you change the current layout object, change the data source of the collection view, or call the
reload method and subsequently request a layout invalidation context.
If this property is set to
true, the layout object should recompute all of its layout-related data.