Is there any different to install UNUserNotificationCenterDelegate in willFinishLaunchingWithOptions or didFinishLaunchingWithOptions? - ios

Question

Currently, this is my code-snippet, in handling tap action, of local notification.
The following code will launch a UIViewController, when user taps on the local notification.
import UIKit
extension UIApplication {
//
// https://stackoverflow.com/a/58031897/72437
//
var keyWindow: UIWindow? {
// Get connected scenes
UIApplication
.shared
.connectedScenes
.compactMap { $0 as? UIWindowScene }
.flatMap { $0.windows }
.first { $0.isKeyWindow }
}
}
#main
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]?) -> Bool {
UNUserNotificationCenter.current().delegate = self
return true
}
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
return true
}
// MARK: UISceneSession Lifecycle
func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
}
func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
}
}
extension AppDelegate: UNUserNotificationCenterDelegate {
// This method is called when user clicked on the notification
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void)
{
let newViewController = NewViewController.instanceFromNib()
newViewController.postInit(response.notification.request.identifier)
UIApplication.shared.keyWindow?.rootViewController?.present(newViewController, animated: false, completion: nil)
completionHandler()
}
}
What I am puzzling is, should I install UNUserNotificationCenterDelegate during willFinishLaunchingWithOptions, or didFinishLaunchingWithOptions?
Install during willFinishLaunchingWithOptions
func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]?) -> Bool {
UNUserNotificationCenter.current().delegate = self
return true
}
Install during didFinishLaunchingWithOptions
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
UNUserNotificationCenter.current().delegate = self
return true
}
Based on https://developer.apple.com/documentation/usernotifications/unusernotificationcenterdelegate
You must assign your delegate object to the UNUserNotificationCenter
object before your app finishes launching. For example, in an iOS app,
you must assign it in the
application(:willFinishLaunchingWithOptions:) or
application(:didFinishLaunchingWithOptions:) method of your app
delegate. Assigning a delegate after the system calls these methods
might cause you to miss incoming notifications.
It seems like there is no difference between willFinishLaunchingWithOptions and didFinishLaunchingWithOptions
I was wondering, do you find any differences, between willFinishLaunchingWithOptions and didFinishLaunchingWithOptions, as far as UNUserNotificationCenterDelegate installation is concerned?
Thanks.