I am trying to check if UserNotifications are enabled and if not I want to throw an alert. So I have a function checkAvailability
which checks multiple things, including the UserNotification authorization status.
func checkAvailabilty() -> Bool {
//
// other checking
//
var isNotificationsEnabled = false
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound], completionHandler: { (granted, error) in
if granted {
isNotificationsEnabled = true
}
else {
isNotificationsEnabled = false
}
})
}
if isNotificationsEnabled {
return true
}
else {
// Throw alert: Remind user to activate notifications
return false
}
}
But the completion handler gets called too late. The function already returned false
and after that the code in the colsure executes.
I tried to put the whole statement UNUserNotificationCenter.current().requestAuthorization()
in a synchronous dispatch queue but this didn't work.
Another approach would be to return from inside the closure but I have no idea how to accomplish that.
Do not wait, use a completion handler, for convenience with an enum:
enum AuthResult {
case success(Bool), failure(Error)
}
func checkAvailabilty(completion: @escaping (AuthResult) -> ()) {
//
// other checking
//
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound], completionHandler: { (granted, error) in
if error != nil {
completion(.failure(error!))
} else {
completion(.success(granted))
}
})
}
And call it:
checkAvailabilty { result in
switch result {
case .success(let granted) :
if granted {
print("access is granted")
} else {
print("access is denied")
}
case .failure(let error): print(error)
}
}