Xcode 7.1 iOS 9.1 CLLocationManager并不总是有效吗？

Question

When implementing a CLLocationManager I came across a problem. Sometimes, when launching the app in the iPhone Simulator, it just doesn't fetch the current locations. But when I restart the app or it then suddenly works after 1-3 restarts. Restarting Xcode works too... Here's my code:

private var lat = 0.0;
private var long = 0.0;

private var didFindLocation = false

let locationManager = CLLocationManager()

override func viewDidLoad() {
    super.viewDidLoad()

    self.locationManager.delegate = self
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
    self.locationManager.requestWhenInUseAuthorization()
    self.locationManager.startUpdatingLocation()

}

func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
    if (status == .AuthorizedAlways) || (status == .AuthorizedWhenInUse) {
        didFindLocation = false
        locationManager.startUpdatingLocation()
    }
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations.last! as CLLocation
    self.lat = location.coordinate.latitude
    self.long = location.coordinate.longitude

    if !didFindLocation {
        print("\(self.lat) - \(self.long)")
        didFindLocation = true
        locationManager.stopUpdatingLocation()
    }
}

As you can see, I've created a bool didFindLocation that allows me to fetch the location only once. I've put some breakpoints to see what's going on, and when the location doesn't get fetched, func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) doesn't even get called.

Thanks

Answer 1

This can happen on a simulator, but do add this method so that you get an error message of why it´s not working even though it´s on a simulator

func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
     print(error.localizedDescription)
}

Answer 2

iOS Simulator do not contains sensors like accelerometer, gyrometer etc, so we should not expect to work them on simulators. Besides this, for fetching a location, perhaps, it is using your system's internet.

So for a fair result it is advisable to use a real device for such cases.

From coding perspective, you can check for locationServicesEnabled property of CCLocationManager to see if this service is enabled or not.

Answer 3

When you check location in simulator then first you need to point your simulator at some location. Why?

Because simulator is not real time device first you need to point it at some position or location.

How you can do it?

There are two ways to do it.

1) select the simulator -> Goto debug -> select location -> select apple location.

Your location method called

Noto : if you select custom location from menu and enter your custom location then you need to restart your simulator (some time multiple times)

2) Goto xcode -> run your project -> in debug panel you find one location icon -> click on it -> it display location name -> select any place name

Note : Not necessary it worked all the times.