Question

How to get game center achievements description into NSString?

Answer 1

Apple makes it very nice for you with this simple block method:

- (void) retrieveAchievmentMetadata {
[GKAchievementDescription loadAchievementDescriptionsWithCompletionHandler:
    ^(NSArray *descriptions, NSError *error) {
        if (error != nil)
            // process the errors
        if (descriptions != nil)
            // use the achievement descriptions.
    }];
}

You can then extract the NSStrings from the descriptions array.

There is more documentation on this topic here: http://developer.apple.com/library/ios/#DOCUMENTATION/NetworkingInternet/Conceptual/GameKit_Guide/Achievements/Achievements.html

I hope this helps!