Contents

addSharedObserver(_:forKey:options:context:)

Add a new observer to the collection.

Declaration

func addSharedObserver(_ observer: NSObject, forKey key: String, options: NSKeyValueObservingOptions = [], context: UnsafeMutableRawPointer?)

Parameters

  • observer:

    The observer object to register for KVO notifications. The observer must implement the key-value observing method observeValue: forKeyPath: of: change: context:

  • key:

    Key of the property being observed. This cannot be a nested key path or a computed property

  • options:

    A combination of NSKeyValueObservingOptions values that specify what is included in observation notifications. For possible values see NSKeyValueObservingOptions.

  • context:

    Arbitrary data which is passed to the observer object

Discussion

This method works like -[NSObject addObserver: forKey: options: context:], but observations on nested and computed properties are disallowed. Observers are not registered until setSharedObservers is called on the observable.