Getting array elements with valueForKeyPath

Question

Is there any way to access an NSArray element with valueForKeyPath? Google\'s reverse geocoder service, for example, returns a very complex data s

Answer 1

You can intercept the keypath in the object holding the NSArray.

In your case the keypath would become Placemark0.address... Override valueForUndefinedKey; look for the index in the keypath; something like this:

-(id)valueForUndefinedKey:(NSString *)key
{
    // Handle paths like Placemark0, Placemark1, ...
    if ([key hasPrefix:@"Placemark"])
    {
        // Caller wants to access the Placemark array.
        // Find the array index they're after.
        NSString *indexString = [key stringByReplacingOccurrencesOfString:@"Placemark" withString:@""];
        NSInteger index = [indexString integerValue];

        // Return array element.
        if (index < self.placemarks.count)
            return self.placemarks[index];
    }

    return [super valueForUndefinedKey:key];
}

This works really well for model frameworks e.g. Mantle.