addObserver(_:selector:name:object:)

Adds an entry to the notification center’s dispatch table with an observer, a selector, and an optional notification name and sender.

Declaration

func addObserver(_ observer: Any, selector aSelector: Selector, name aName: NSNotification.Name?, object anObject: String?)

observer:
An object registering as an observer.
aSelector:
A selector that the notification center sends notificationObserver to notify when posting the notification.
aName:
The name of the notification for which to register the observer; that is, only notifications with this name are delivered to the observer. When nil, the notification center doesn’t use a notification’s name to decide whether to deliver it to the observer.
anObject:
The object whose notifications the observer wants to receive; that is, only notifications sent by this sender are delivered to the observer. When nil, the notification center doesn’t use a notification’s sender to decide whether to deliver it to the observer.