locationServicesEnabled for iOS 3 and iOS 4

Question

locationServicesEnabled changed from a property to a method.

This is deprecated:

CLLocationManager *manager = [[CLLocationManager alloc] init];
if (manager.locationServicesEnabled == NO) {
     // ...
}

Now I should use:

if (![CLLocationManager locationServicesEnabled]) {
    // ...
}

I want to support iOS 3 and iOS 4 devices. How can I check this on iOS 3 devices and get rid of the deprecated warning?

Answer 1

Editted:

#if __IPHONE_OS_VERSION_MIN_REQUIRED > __IPHONE_3_1
  #if __IPHONE_OS_VERSION_MIN_REQUIRED > __IPHONE_3_2
    if (![CLLocationManager locationServicesEnabled]) {
    // ...
    }
  #else
    CLLocationManager *manager = [[CLLocationManager alloc] init];
    if (manager.locationServicesEnabled == NO) {
       // ...
    }
  #endif
#else
CLLocationManager *manager = [[CLLocationManager alloc] init];
if (manager.locationServicesEnabled == NO) {
     // ...
}
#endif

Answer 2

Followup question: how can conditional compiling support different devices at runtime ? If I were to compile this on a 4.0 SDK, it would not run legitimately on a 3.1.3 device, because it would call the method, not the property, and that's not a supported API for 3.1.3. So wouldn't that be cause for rejection by Apple? Clearly I'm confused.

Answer 3

Try:

BOOL locationServicesEnabled;
CLLocationManager locationManager = [CLLocationManager new];
if( [locationManager respondsToSelector:@selector(locationServicesEnabled) ] )
{
    locationServicesEnabled = [locationManager locationServicesEnabled];
}
else
{
    locationServicesEnabled = locationManager.locationServicesEnabled;
}

As a fix/work around.

Using the compiler defines will cause you issues when using the minimum deployment target to allow older OS versions access to your application.