The identifier that determines whether the view supports state restoration.
- iOS 6.0+
- tvOS 9.0+
This property indicates whether state information in the view should be preserved; it is also used to identify the view during the restoration process. The value of this property is
nil by default, which indicates that the view’s state does not need to be saved. Assigning a string object to the property lets the owning view controller know that the view has relevant state information to save.
Assign a value to this property only if you are implementing a custom view that implements the
decode methods for saving and restoring state. You use those methods to write any view-specific state information and subsequently use that data to restore the view to its previous configuration.