iPhone Development - CLLocationManager vs. MapKit

Question

If i want to show userLocation on the map, and at the same time record the user's location, is it a good idea to add an observer to userLocation.location and record the locations, OR should i still use CLLocationManager for recording user location and use mapView.showUserLocation to show the user's current location (blue indicator)? I want to show the default blue indicator supported by the MapKit API.

Also, here's a rough sample code:

- (void)viewDidLoad {
    ...

    locationManager = [[CLLocationManager alloc] init]; 
    locationManager.desiredAccuracy = kCLLocationAccuracyBest; 
    locationManager.distanceFilter = DISTANCE_FILTER_VALUE;
    locationManager.delegate = self; 
    [locationManager startUpdatingLocation];

    myMapView.showUserLocation = YES;
    [myMapView addObserver:self forKeyPath:@"userLocation.location" options:0 context:nil];

    ...
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    // Record the location information
    // ...
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { 
    NSLog(@"%s begins.", __FUNCTION__);

    // Make sure that the location returned has the desired accuracy
    if (newLocation.horizontalAccuracy <= manager.desiredAccuracy)
        return;

    // Record the location information
    // ...
}

Under the hood, i think MKMapView also uses CLLocationManager to get user's current location? So, will this create any problems because i believe both CLLocationManager and MapView will try to use same location services? Will there be any conflicts and lack of accurate/required or current data?

score 1 · Accepted Answer · edited May 23 '17 at 09:57

1

See this SO entry: CLLocationManager uses the same data across all of its instances, so there is no conflict.

edited May 23 '17 at 09:57

Community

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1

answered Apr 07 '10 at 08:07

Laurent Etiemble

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But if we set showUserLocation to TRUE and create a CLLocationManager in our custom class, we're essentially making two instances of CLLocationManager - one used by MKMapView and one in your custom class. Who'll get the location updates? The observer on userLocation.location or the didUpdateLocation: delegate method? If i start recording the locations in both of these, will the recorded locations be in sync? – Mustafa Apr 07 '10 at 08:33
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Apparently, you can have multiple Location Managers and they'll give you accurate information. Although MapKit also uses CLLocationManager under the hood, creating a CLLocationManager and using it with MapKit won't create any conflicts. – Mustafa Apr 13 '10 at 04:54

iPhone Development - CLLocationManager vs. MapKit

1 Answers1