iOS 8 Map Kit Obj-C Cannot Get Users Location

Question

I am working with Map Kit in iOS 8 using Obj-C NOT SWIFT. I cannot get the device location it is set a 0.00, 0.00 and I am getting the error:

Trying to start         


        

Answer 1

Try This One:

 (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status {

    if (status == kCLAuthorizationStatusAuthorizedWhenInUse) {
        self.mapView.showsUserLocation = YES;
    }

Answer 2

I had the same problem but adding these two line in plist file solved my problems

NSLocationWhenInUseUsageDescription

And

NSLocationAlwaysUsageDescription

NOTE : Must provide string description of both these values. You can use any of them in your controller file as below

self.locationManager= [[CLLocationManager alloc] init];
self.locationManager.delegate=self;
[self.locationManager requestAlwaysAuthorization];

You must implement CLLOcationManagerDelegate in your controller to access this functionality

Answer 3

Further to Mikes answer, I found that using both [self.locationManager requestWhenInUseAuthorization]; and [self.locationManager requestAlwaysAuthorization]; as demonstrated in his code does not work. You should only use ONE.

I assume some further changes were made with a more recent/stable version of the API.

Answer 4

I got it working. I've posted my code below to help anyone else having issues.

Here is my full code to get the MapKit Map View working in iOS 8.

In your AppName-Info.plist Add a new row with the key name being:

NSLocationWhenInUseUsageDescription

Or

NSLocationAlwaysUsageDescription

With the value being a string of the message that you want to be displayed:

YourAppName would like to use your location.

In your header file. (I use App Name-Prefix.pch but YourViewController.h will work too)

#define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

YourViewController.h

#import <MapKit/MapKit.h>
#import <MapKit/MKAnnotation.h>

@interface YourViewController : UIViewController <MKMapViewDelegate,  CLLocationManagerDelegate> {

}


@property(nonatomic, retain) IBOutlet MKMapView *mapView;
@property(nonatomic, retain) CLLocationManager *locationManager;

YourViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.


    mapView.delegate = self;
    self.locationManager = [[CLLocationManager alloc] init];
    self.locationManager.delegate = self;
    #ifdef __IPHONE_8_0
    if(IS_OS_8_OR_LATER) {
         // Use one or the other, not both. Depending on what you put in info.plist
        [self.locationManager requestWhenInUseAuthorization];
        [self.locationManager requestAlwaysAuthorization];
    }
    #endif
    [self.locationManager startUpdatingLocation];

    mapView.showsUserLocation = YES;
    [mapView setMapType:MKMapTypeStandard];
    [mapView setZoomEnabled:YES];
    [mapView setScrollEnabled:YES];
}

-(void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:YES];

    self.locationManager.distanceFilter = kCLDistanceFilterNone;
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    [self.locationManager startUpdatingLocation];
    NSLog(@"%@", [self deviceLocation]);

    //View Area
    MKCoordinateRegion region = { { 0.0, 0.0 }, { 0.0, 0.0 } };
    region.center.latitude = self.locationManager.location.coordinate.latitude;
    region.center.longitude = self.locationManager.location.coordinate.longitude;
    region.span.longitudeDelta = 0.005f;
    region.span.longitudeDelta = 0.005f;
    [mapView setRegion:region animated:YES];

}

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(userLocation.coordinate, 800, 800);
    [self.mapView setRegion:[self.mapView regionThatFits:region] animated:YES];
}
- (NSString *)deviceLocation {
    return [NSString stringWithFormat:@"latitude: %f longitude: %f", self.locationManager.location.coordinate.latitude, self.locationManager.location.coordinate.longitude];
}
- (NSString *)deviceLat {
    return [NSString stringWithFormat:@"%f", self.locationManager.location.coordinate.latitude];
}
- (NSString *)deviceLon {
    return [NSString stringWithFormat:@"%f", self.locationManager.location.coordinate.longitude];
}
- (NSString *)deviceAlt {
    return [NSString stringWithFormat:@"%f", self.locationManager.location.altitude];
}

Enjoy!

--Mike

Answer 5

Your code looks fine, though you do not need to call requestWhenInUseAuthorization and the other requestAlwaysAuthorization , choose one you need.

Code for displaying locations is just yet allocating locationManager, do not expect to get location data instantly.

you need to wait till delegate method gets called : -(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
, then self.locationManager.location will also be set.

Answer 6

It's not written anywhere, but if your app starts with MapKit, you will still receive the error message "Trying to start MapKit location updates without prompting for location authorization" even after implementing MBarton's answer. To avoid it, you have to create a new view controller before the MapKit, and implement the location manager delegates there. I called it AuthorizationController.

So, in AuthorizationController.h:

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>

@interface MCIAuthorizationController : UIViewController <CLLocationManagerDelegate>

@property (strong, nonatomic) CLLocationManager *locationManager;

@end

And in AuthorizationController.m:

- (void)viewDidLoad {
    [super viewDidLoad];

    // Location manager
    self.locationManager = [[CLLocationManager alloc] init];
    self.locationManager.delegate = self;

    // Check for iOS 8. Without this guard the code will crash with "unknown selector" on iOS 7.
    if ([self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [self.locationManager requestWhenInUseAuthorization];
    }
}

#pragma mark - Location Manager delegates

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
    NSLog(@"didUpdateLocations: %@", [locations lastObject]);
}


- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    NSLog(@"Location manager error: %@", error.localizedDescription);
}

- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status {
    if (status == kCLAuthorizationStatusAuthorizedWhenInUse) {
        [self.locationManager startUpdatingLocation];
        [self performSegueWithIdentifier:@"startSegue" sender:self];
    } else if (status == kCLAuthorizationStatusDenied) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Location services not authorized"
                                                        message:@"This app needs you to authorize locations services to work."
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
    } else
        NSLog(@"Wrong location status");
}