Observables does not send updated value when app enters foreground

[havard024]

Our app requires the user to allow access to the devices location.
To handle this we first check if the location service is enabled, if it's not enabled we present a view controller letting the user know that he / she needs to enable the location service to continue.
The user would then most likely put the app in the background, enable the location service, open the app again.

In the view we present to the user when location service is disabled, we would like to automatically detect if the location service has been enabled, the code below is our attempt to react to the isEnabled event.

viewDidLoad() {
  super.viewDidLoad()
  manager.rx
    .isEnabled
    .debug("isEnabled")
    .subscribe(onNext: { isEnabled in
      if isEnabled {
        DispatchQueue.main.async {
          self.dismiss(animated: true, completion: nil)
        }
      }
    })
    .disposed(by: bag)
}

When we test this by putting the app in the background then to foreground, no event is triggered.

Is this something the library is designed to handle?

If not, how would one go about creating this functionality in an app?

[bobgodwinx]

By the way this is the wrong way to do subscription. you should use subscribeOn(MainScheduler.instance) instead.
And you are also missing something before the call of manager.rx...

        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()

please see the example project for more

[unxavi]

Hi,

Why do you need to startUpdatingLocation to know if location services are on? this is a static method of CLLocationManager and shouldn't be related between them.

Using the example I project config, I also see that sometimes it's not deliver in background when you go to settings and change locations services on/off

[havard024]

@bobgodwinx I'm referring to the example on line 85

manager.rx
    .isEnabled
    .debug("isEnabled")
    .subscribe(onNext: { _ in })
    .disposed(by: bag)

[bobgodwinx]

@havard024 I think I now understand what you're trying todo here. Correct me if I am wrong.

1. You are putting the app in background and disactivating location services correct ?

[havard024]

@bobgodwinx Yes exactly and when you put the app in foreground again, there is no event to notify that the location service is disabled

[bobgodwinx]

@havard024 Here is my advice: The API is actually working as expected. The event you are expecting is not emitted because CLLocationManager actually emitted Error events which you could use for this purpose.

• didError -> Event next((manager: <CLLocationManager: 0x600003acbfb0>, error: Error Domain=kCLErrorDomain Code=1 "(null)")) the code here is 1 which means kCLErrorDenied.
• This error is actually indicating that the manager is locked out of CLLocationManager
• would rather use another event here which is the didChangeAuthorization that also gets emitted when you try switching of the LocationServices

        manager.rx
            .didChangeAuthorization
            .debug("didChangeAuthorization")
            .subscribe(onNext: { e in
                let a = e.status
                switch a {
                case .denied, .notDetermined, .restricted:
                    print("Stay there blocking the screen! don't move")
                default:
                    print("Stop blocking the screen let him enter now")
                }
            })
            .disposed(by: bag)

Let me know if this helps.