Question

I need to call

[[MKLocationManager sharedLocationManager] _applyChinaLocationShift:newLocation]

in my iOS app.

I believe MKLocationManager is a private class, and there does not seem to have a MapKit/MKLocationManager.h file.

I’m not targeting App Store. It’s there any way I can use that private API?

Update at 2011-6-23

I really need the answer, or could I de-complie the iOS SDK?

100 reputation is almost all I have. Please help me.

Answer 1

If the above answer isn’t working for you, this may be because the entire class is private (including it’s header). Here’s an alternative approach using some runtime trickery; you must be sure that the signature is correct but we can use some defensive coding to avoid a crash.

First, unless you are calling this just once, I’d wrap up the code in a helper method:

// in some header file, you may want to give the method a prefix too
CLLocation *ApplyLocationManagerChinaLocationShift(CLLocation *newLocation);

You can now use NSClassFromString to obtain a reference to the class and performSelector to perform the method. We can try and make sure the method exists first to be on the safe side:

CLLocation *ApplyLocationManagerChinaLocationShift(CLLocation *newLocation)
{
  id sharedLocationManager = [NSClassFromString(@"MKLocationManager") performSelector:@selector(sharedLocationManager)];

  SEL theSelector = @selector(_applyChinaLocationShift:);

  // this will ensure sharedLocationManager is non-nil and responds appropriately
  if (![sharedLocationManager respondsToSelector:theSelector]) {
    return nil; // fail silently - check this in the caller
  }
  return [sharedLocationManager performSelector:theSelector withObject:newLocation];
}

I haven’t run the above code but it should do the trick. If for some reason the @selector() calls do not work (I think they should), then you can replace them with NSSelectorFromString() calls instead.