Question

If a user has turned off location services (either for all apps or just mine), CLLocationManager never prompts and never updates the position. This is to be expected, but is there a way to detect that location services is turned off, and prompt to reenable it?

Answer 1

Just to complete Tim’s answer.

You can always try starting location updates via startUpdatingLocation method on CLLocationManager instance. If location services are disabled, you’ll get notified about error condition by delegate and then you can bring up the dialog asking user to go into Settings and enable location services for your app…

#pragma mark - CLLocationManagerDelegate
- (void)locationManager:(CLLocationManager *)inManager didFailWithError:(NSError *)inError{
    if (inError.code ==  kCLErrorDenied) {
        NSLog(@"Location manager denied access - kCLErrorDenied");
        // your code to show UIAlertView telling user to re-enable location services
        // for your app so they can benefit from extra functionality offered by app
    }
}

Please note that you can launch Settings app via URL-scheme on iOS5 (versions lower than 5.0 (and greater than 5.0), don’t support it). Call:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs://"]];