WatchOS: getting applicationDidBecomeActive notifications

Question

I'm making a framework that needs to do stuff when my apple watch is entering background and foreground.

I'm looking for an equivalent of this iOS code for the Apple watch since UIApplication is not present in UIKit anymore :

let notificationCenter = NSNotificationCenter.defaultCenter()
notificationCenter.addObserver(self, selector: "applicationDidEnterBackground", name: UIApplicationDidEnterBackgroundNotification, object: nil)

any help would be nice

Answer 1

As of watchOS 7 the following have been added:

WKExtension.applicationDidBecomeActiveNotification
WKExtension.applicationDidEnterBackgroundNotification
WKExtension.applicationDidFinishLaunchingNotification
WKExtension.applicationWillEnterForegroundNotification
WKExtension.applicationWillResignActiveNotification

Source: https://developer.apple.com/documentation/WatchKit/wkextension

Answer 2

Appears that the WatchOS equivalent of

let notificationCenter = NSNotificationCenter.defaultCenter()
notificationCenter.addObserver(self, selector: "applicationDidEnterBackground", name: UIApplicationDidEnterBackgroundNotification, object: nil)

is simply

let notificationCenter = NSNotificationCenter.defaultCenter()
notificationCenter.addObserver(self, selector: "applicationDidEnterBackground", name: "UIApplicationDidEnterBackgroundNotification", object: nil)

One just need to replace the emum by its string equivalent