getDistanceFrom Vs distanceFromLocation

Question

Hello,

I'm having a problem with getDistanceFrom and distanceFromLocation. getDistanceFrom is deprecated iOS 4.1 and distanceFromLocation is not available in 3.1.3, how do I get around this problem.

Has anyone else come across this problem ?

My code at the moment is:

CLLocationDistance kilometers;
        if ([currentLocation respondsToSelector: @selector(distanceFromLocation:)])
        {
            kilometers = [currentLocation distanceFromLocation:previousLocation] / 1000;
        }
        else
        {
            //kilometers = [currentLocation getDistanceFrom:previousLocation] / 1000;
            kilometers = [currentLocation performSelector: @selector(getDistanceFrom:) withObject: previousLocation] / 1000;
        }

Depending on which iOS I compile with I'm getting 'invalid operands to binary' on the lines:

kilometers = [currentLocation distanceFromLocation:previousLocation] / 1000;
            kilometers = [currentLocation performSelector: @selector(getDistanceFrom:) withObject: previousLocation] / 1000;

Regards, Stephen

Answer 1

There's a blog post by Cédric Luthi which has a pretty good solution to this.

In short, you need to enter the following into your main.m and make sure to #import <objc/runtime.h> :

Method getDistanceFrom = class_getInstanceMethod([CLLocation class], @selector(getDistanceFrom:));
class_addMethod([CLLocation class], @selector(distanceFromLocation:), method_getImplementation(getDistanceFrom), method_getTypeEncoding(getDistanceFrom));

You can then use distanceFromLocation: on any OS.