ios - 如何防止通知设置被重复注册？

Question

我正在我的 AppDelegate.didFinishLaunchingWithOptions 事件中注册通知设置，如下所示:

let notificationType = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound
let acceptAction = UIMutableUserNotificationAction()
acceptAction.identifier = "Accept"
acceptAction.title = "Accept"
acceptAction.activationMode = UIUserNotificationActivationMode.Background
acceptAction.destructive = false
acceptAction.authenticationRequired = false

let declineAction = UIMutableUserNotificationAction()
declineAction.identifier = "Decline"
declineAction.title = "Decline"
declineAction.activationMode = UIUserNotificationActivationMode.Background
declineAction.destructive = false
declineAction.authenticationRequired = false

let category = UIMutableUserNotificationCategory()
category.identifier = "invite"
category.setActions([acceptAction, declineAction], forContext: UIUserNotificationActionContext.Default)
let categories = NSSet(array: [category])
let settings = UIUserNotificationSettings(forTypes: notificationType, categories: categories)
application.registerUserNotificationSettings(settings)

如何防止我的应用程序注册两次，以防用户退出应用程序并稍后返回，或者多次重新注册是否无害？

Answer 1

用户被提示一次通知后，就不会再被询问。您可以在模拟器中亲自验证这一点。因此，那里的代码原样就很好。