Attempt to present <a> on <a> while a presentation is in progress - swift

Question

i know this has been asked before but i'm trying to figure out the issue with my project, as the title states (a) is trying to present on (a) i have checked all segue triggers to see if i accidentally set a segue to go to the same view controller that it is already on but this is not the case.
view controller 1 code
import UIKit
import UserNotifications
class NotificationViewController: UIViewController {
let isRegisteredForRemoteNotifications = UIApplication.shared.isRegisteredForRemoteNotifications
let current = UNUserNotificationCenter.current()
#IBAction func Notification(_ sender: Any) {
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge], completionHandler: {didAllow, error in})
var i = 0
while i < 1{
current.getNotificationSettings(completionHandler: { (settings) in
if settings.authorizationStatus == .notDetermined {
// Notification permission has not been asked yet, go for it!
}
if settings.authorizationStatus == .denied {
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was previously denied, go to settings & privacy to re-enable
}
}
if settings.authorizationStatus == .authorized {
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was already granted
}
}
})
}
}
override func viewDidLoad() {
current.getNotificationSettings(completionHandler: { (settings) in
if settings.authorizationStatus == .notDetermined {
// Notification permission has not been asked yet, go for it!
}
if settings.authorizationStatus == .denied {
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was previously denied, go to settings & privacy to re-enable
}
}
if settings.authorizationStatus == .authorized {
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLocation", sender: self)
// Notification permission was already granted
}
}
})
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
view controller 2 code
import UIKit
import CoreLocation
class LocationViewController: UIViewController {
#IBOutlet weak var textview: UITextView!
let locationManager = CLLocationManager()
#IBAction func OnLocation(_ sender: Any) {
locationManager.delegate = self as? CLLocationManagerDelegate
var i = 0
while i < 1{
switch CLLocationManager.authorizationStatus() {
case .notDetermined:
// Request when-in-use authorization initially
locationManager.requestWhenInUseAuthorization()
break
case .restricted, .denied:
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLogin", sender: self)
}
// Disable location features
//disableMyLocationBasedFeatures()
break
case .authorizedWhenInUse:
i = i + 1
DispatchQueue.main.async {
self.performSegue(withIdentifier: "ToLogin", sender: self)
}
// Enable basic location features
//enableMyWhenInUseFeatures()
break
case .authorizedAlways:
// Enable any of your app's location features
// enableMyAlwaysFeatures()
break
}
}
}
override func viewDidLoad() {
func locationManager(_ manager: CLLocationManager,
didChangeAuthorization status: CLAuthorizationStatus) { switch status {
case .restricted, .denied:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .authorizedWhenInUse:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .authorizedAlways:
self.performSegue(withIdentifier: "ToLogin", sender: self)
break
case .notDetermined:
break
}
}
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
error message
018-02-27 23:06:41.534749+1030 Request[27358:1351259] Warning: Attempt
to present on
while a presentation
is in progress!

Answer 1

No no no no no. This is not the way. sorry about this plenty of no´s but completionHandler result parameter of the requestAuthorization method from UNUserNotification may be executed on a background thread.
tips for this function
#IBAction func Notification(_ sender: Any)
*should start with lowercase
*provide a name that the action it accomplish can be inferred by that name
*change the type of the sender (if you know it), that way you can explicitly call properties or methods on that object without cast.
continuing with the rest of the code inside the scope of the function. requestAuthorization have the only responsibility of that - ask for a permission - and the response is didAllow or error. You never check this and continue launching another block that response is also another thread
bottom line: your calling requestAuthorization and then getNotificationSettings inside a loop (why?), you have a lot of luck if this code execute 30% of the time.
So you should separate some of the code involving permissions, read some lines about GRASP principle, also read every chapter here

Answer 2

Your error message is pretty clear while a presentation is in progress. That mean that you try to present LocationViewController from another LocationViewController, but it still not presented yet.
Move your presentation logic to viewWillAppear method. It will help
UPDATE
1) remove your existing segue from Notification button to LocationViewController in storyboard
2) Add segue from NotificationViewController to LocationViewController like it shown on picture
3) Set name for this segue
Now try to run your project