Google Maps API for iOS myLocationEnabled not work

问题:

I am trying to use the Google Maps API but am having trouble getting the user's location. The observed value never seems to change since observeValueForKeyPath is never called.
Note: I am running Xcode6-Beta 5 and iOS8 beta (code is in Swift)

override func viewDidLoad() {
    super.viewDidLoad()
    var camera:GMSCameraPosition? = nil
    mapView_ = GMSMapView.mapWithFrame(CGRectZero, camera:camera);
    mapView_!.addObserver(self, forKeyPath: "myLocation", options: NSKeyValueObservingOptions.fromRaw(0x01)!, context: nil);
    camera = GMSCameraPosition.cameraWithTarget(mapView_!.myLocation.coordinate, zoom: 6);
    mapView_!.camera = camera;


    self.view = mapView_;
    dispatch_async(dispatch_get_main_queue(), {
        mapView_!.myLocationEnabled = true;
        });

}
override func observeValueForKeyPath(keyPath: String!, ofObject object: AnyObject!, change: [NSObject : AnyObject]!, context: UnsafeMutablePointer<()>) {
    if (keyPath == "myLocation" && object.isKindOfClass(GMSMapView)) {
        mapView_!.animateToCameraPosition(GMSCameraPosition.cameraWithTarget(mapView_!.myLocation.coordinate, zoom: 6));
    }

}

回答1:

As of right now, Google Maps iOS SDK hasn't been updated to support iOS 8. So in order to use the location features, you're going to need to do the iOS 8 location authorization yourself.

You can do this by instantiating a CLLocationManager object and executing either -requestWhenInUseAuthorization or -requestAlwaysAuthorization on that. You'll need to do this before setting myLocationEnabled to YES.

Be sure to also include the necessary keys in your Info.plist file. If you are wanting to use always authorization (as in the code example below), provide NSLocationAlwaysUsageDescription, or if you want when in use authorization, NSLocationWhenInUseUsageDescription. One of them is required, and if you don't provide it, location features won't work.

Here's an example in Obj-C. Sorry, I'm not up to date with all the Swift stuff yet. :)

// Rather than setting -myLocationEnabled to YES directly,
// call this method:

- (void)enableMyLocation
{
    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];

    if (status == kCLAuthorizationStatusNotDetermined)
        [self requestLocationAuthorization];
    else if (status == kCLAuthorizationStatusDenied || status == kCLAuthorizationStatusRestricted)
        return; // we weren't allowed to show the user's location so don't enable
    else
        [self.view setMyLocationEnabled:YES];
}

// Ask the CLLocationManager for location authorization,
// and be sure to retain the manager somewhere on the class

- (void)requestLocationAuthorization
{
    _locationAuthorizationManager = [[CLLocationManager alloc] init];
    _locationAuthorizationManager.delegate = self;

    [_locationAuthorizationManager requestAlwaysAuthorization];
}

// Handle the authorization callback. This is usually
// called on a background thread so go back to main.

- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    if (status != kCLAuthorizationStatusNotDetermined) {
        [self performSelectorOnMainThread:@selector(enableMyLocation) withObject:nil waitUntilDone:[NSThread isMainThread]];

        _locationAuthorizationManager.delegate = nil;
        _locationAuthorizationManager = nil;
    }
}

回答2:

Here is the code for others facing the same issue in iOS swift:

Add Delegates:

GMSMapViewDelegate, CLLocationManagerDelegate

Variables:

    @IBOutlet var gmaps: GMSMapView?
    var firstLocationUpdate: Bool?
    let locationManager = CLLocationManager()

Function:

func startMaps() {

        locationManager.delegate = self;
        locationManager.distanceFilter = kCLDistanceFilterNone;
        locationManager.desiredAccuracy = kCLLocationAccuracyBest;

        locationManager.startUpdatingLocation()
        locationManager.requestWhenInUseAuthorization()

        let location: CLLocation = locationManager.location

        var target: CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude)
        var camera: GMSCameraPosition = GMSCameraPosition(target: target, zoom: 6, bearing: 0, viewingAngle: 0)

        if let map = gmaps? {
            map.myLocationEnabled = true
            map.camera = camera
            map.delegate = self
        }
    }

Hope this will help.

回答3:

Please don't forget to add this in Info.plist

<key>NSLocationWhenInUseUsageDescription</key>
    <true/>
<key>NSLocationAlwaysUsageDescription</key>
    <true/>