How to check if user clicks no on NSLocationAlwaysAndWhenInUseUsageDescription Swift 3.2 - ios

Question

When user is on MainViewController
override func viewDidLoad() {
super.viewDidLoad()
locationManager.delegate = self
locationManager.requestAlwaysAuthorization()
locationManager.requestWhenInUseAuthorization()
}
viewDidLoad() will run and the alert will appear
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>Accessing user location to determine the nearest pickup location</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>Accessing user location to determine the nearest pickup location</string>
The main question is, if user clicks Don't allow, how do I check programmtically? for example
// Example code snippet, not from apple officials
if NSlocation is nil then I want to do some alert

Answer 1

If the user chooses to deny your app access to location services, CLLocationManager.authorizationStatus() will be .denied (though you should also watch out for .restricted. If you'd like to be notified when the user chooses whether or not to allow or deny your app, you can make yourself your location manager's delegate and implement the proper method:
class MainViewController: CLLocationManagerDelegate{
let locationManager = CLLocationManager()
override func viewDidLoad() -> Void{
super.viewDidLoad()
locationManager.delegate = self
}
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) -> Void{
switch status{
case .authorizedAlways, .authorizedWhenInUse:
// You're allowed to use location services
case .denied, .restricted:
// You can't use location services
default:
// This case shouldn't be hit, but is necessary to prevent a compiler error
}
}
}

Answer 2

Use below delegate method of CLLocationManager to check user click on Don't allow button in permission alert.
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
switch status {
case .denied:
print("Show you own alert here")
break
}
}
To redirect user in location settings follow below:
Add URL Types "prefs" like below image
Write this code on button action:
UIApplication.sharedApplication().openURL(NSURL(string:"prefs:root=LOCATION_SERVICES")!)