iOS要求始终授权的iOS首次显示权限警报

Question

Fist time when I install my iOS app on a device via xcode and location service is off, requestAlwaysAuthorization() shows "Turn on location services" that push user to device Settings to turn on location service, then user comes back to the app and would see "permission" alert(with three options always, while using and never). If user taps on always option then closes the app completely and turns location service off then opens app again, "Turn on location services" alert is not displayed. This is my code:

override func viewDidLoad() {
    super.viewDidLoad()

    locationManager = CLLocationManager()
    NotificationCenter.default.addObserver(self, selector: #selector(checkLocationService), name: Notification.Name.UIApplicationWillEnterForeground, object: nil)    
}

 @objc func checkLocationService() {
    if CLLocationManager.locationServicesEnabled() {
        switch CLLocationManager.authorizationStatus() {
        case .denied, .notDetermined, .restricted:
            locationManager = CLLocationManager()
            locationManager.delegate = self
            locationManager.requestAlwaysAuthorization()
        case .authorizedWhenInUse, .authorizedAlways:
            ...
        }
    } else {
        locationManager = CLLocationManager()
        locationManager.delegate = self
        locationManager.requestAlwaysAuthorization()
    }
}

I've added all three location keys in the Info.plist:

<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>My app need your location to work</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>My app need your location to work</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>My app need your location to work</string>

I am testing on iOS 11 and 12 and I have no idea what is wrong.

Answer 1

You only request auth once... if the user grants permission then you dont need to ask again and if they refuse you can't prompt again. you need to handle it differently if denied. you push the user to the app settings in the settings menu and the user has to enable from there

switch CLLocationManager.authorizationStatus() {
    case .notDetermined, .restricted:
        locationManager = CLLocationManager()
        locationManager.delegate = self
        locationManager.requestAlwaysAuthorization()
    case .authorizedWhenInUse, .authorizedAlways:
        ...
    case .denied:
        // present an alert advising the user that they need to go to the settings menu to enable the permissions as they have previously denied it. 
        // if the user presses Open Settings on the alert....
        if let url = URL(string: UIApplicationOpenSettingsURLString) { 
            UIApplication.shared.open(url: url) 
        }
    }