Checking for iOS Location Services

I have a view with a map and a button (like the Maps app once) that allows the user to center and zoom his current location on the map. If I can not use the locationServicesEnabled method (always returns YES), should I create a BOOL attribute to check if the didFailWithError method is called and know if I can call the button method?

Thanks for reading.

Edited:

This code does not work for me. I am using the simulator. I am always getting YES when asking locationServicesEnabled.

// Gets the user present location.
- (IBAction)locateUser:(id)sender {

    if([CLLocationManager locationServicesEnabled]) {

        C开发者_如何学运维LLocationCoordinate2D coordinate;

        coordinate.latitude = self.mapView.userLocation.location.coordinate.latitude;
        coordinate.longitude = self.mapView.userLocation.location.coordinate.longitude;

        [self zoomCoordinate:coordinate];
    } else {
        [[[[UIAlertView alloc] initWithTitle:@"Warning." message:@"Location services are disabled." 
                                    delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease] show];     
    }
}

In Preferences you have two options to disable the location services. The first option is a global switch to disable the location service for all apps "[CLLocationManager locationServicesEnabled]". The second option let you disable the location service for some apps but not for all apps.

To check if its disabled globally and if its disabled for your app use following:

if([CLLocationManager locationServicesEnabled] && 
   [CLLocationManager authorizationStatus] != kCLAuthorizationStatusDenied)
{
...
}

"locationServicesEnabled" checks if the user has enabled Location Services in Preferences. Your MapView probably checks this value already and should not set any values to "self.mapView.userLocation" if Location Services are not available. This SO question might give you some more info.

I run into this problem too and still be finding the answer.

take care that authorizationStatus requires iOS4.2+ and + (BOOL)locationServicesEnabled requires iOS4.0... And for previous iOS versions, it is - (BOOL)locationServicesEnabled...

- (BOOL) enableLocationServices
{

    if ([CLLocationManager locationServicesEnabled])
    {
        self.locationManager.distanceFilter = 10;
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        [self.locationManager startUpdatingLocation];
        [self.mapview setUserTrackingMode:MKUserTrackingModeFollow animated:YES];
        return YES;
    }
    else
    {
        return NO;
    }
}