MKMapView or CLLocationManger - to determine user's current location - ios

Question

There are two classes that help regarding map plotting and determining user location - MKMapView and CLLocationManager.
MKMapView has a delegate “didUpdateUserLocation” that tells the user’s current location. At the same time, CLLocationManger has a delegate “didUpdateToLocation” and it also does the same thing.
My question is when to use MKMapView and CLLocationManager. I am able to get current location of the device from MKMapView then why and when should I use CLLocationManager? I tried to get it but I am still not sure.

Answer 1

I think you are confusing the MKMapView property showsUserLocation with CLLocationManager.
As a convenience MKMapView's allow you to simply enable a property to show the users current location on the map UI. This is really handy if you only need to show the user where they are on a map.
However, there are demonstrably many other use cases where simply showing location on a map is not enough and this is where CLLocationManager comes in.
Consider for example a running/training application, where a record of user locations is required to calculate running distance, or even an example from one of my own applications, where by I needed to find the users location (lat/long) to calculate distance to various train stations in real time to identify which was closest for the user. In these examples there is no need for a MapView so using a LocationManager is the right choice.
Anytime you need to programmatically interact with the users location and don't require a map UI basically!

Answer 2

I prefer to use CLLocationManager which is used internally by the MKMapView, so if you don't need to use the map, just use the below code from the location manager.
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.delegate = self;
[locationManager startUpdatingLocation];
Just don't forget to store the locationManager instance somewhere in your class and you can implement the delegate like this.
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
NSLog(#"Error detecting location %#", error);
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
CLLocation* location = (CLLocation*)locations.lastObject;
NSLog(#"Longitude: %f, Latitude: %f", location.coordinate.longitude, location.coordinate.latitude);
}
EDIT
You can get the address of the user based on their location using Apple's Geo coder
// Use Apple's Geocoder to figure the name of the place
CLGeocoder* geoCoder = [[CLGeocoder alloc] init];
[geoCoder reverseGeocodeLocation:location completionHandler: ^(NSArray* placemarks, NSError* error) {
if (error != nil) {
NSLog(#"Error in geo coder: %#", error);
}
else {
if (placemarks.count == 0) {
NSLog(#"The address couldn't be found");
}
else {
// Get nearby address
CLPlacemark* placemark = placemarks[0];
// Get the string address and store it
NSString* locatedAt = [[placemark.addressDictionary valueForKey:#"FormattedAddressLines"] componentsJoinedByString:#", "];
location.name = locatedAt;
NSLog(#"The address is: %#", locatedAt);
}
}
}];