Translate language code with Xcode 6.1 using NSLocale - ios

Question

Since the last update, I can't translate the language code (en, fr, etc...) into their respective names (English, French, etc...).
It works on a real device, but not in the emulator. It was working using former versions of Xcode. I'm aware that it's written in the release notes that [NSLocale currentLocale] may return en_US in some situations, but that doesn't explain why they are no more "translated". I use this code:
NSString* lang = #"en";
NSLog(#"%#",
[[NSLocale currentLocale]
displayNameForKey:NSLocaleIdentifier
value:lang]
);
which displays (null), instead of English.
The problem is that my app is crashing at some places because of that so I would like to know if there's a workaround.
The weird thing is that the following example, given by Apple, works really well.
NSLocale *frLocale = [[NSLocale alloc] initWithLocaleIdentifier:#"fr_FR"];
NSString *displayNameString = [frLocale displayNameForKey:NSLocaleIdentifier value:#"fr_FR"];
NSLog(#"displayNameString fr_FR: %#", displayNameString);
displayNameString = [frLocale displayNameForKey:NSLocaleIdentifier value:#"en_US"];
NSLog(#"displayNameString en_US: %#", displayNameString);

Answer 1

From Xcode release note
In some situations, [NSLocale currentLocale] may return en_US instead
of the chosen locale in the iOS 8.1 simulator. (18512161)
+ (NSLocale *)autoupdatingCurrentLocale NS_AVAILABLE(10_5, 2_0); // generally you should use this method
+ (NSLocale *)currentLocale; // an object representing the user's current locale
A workaround is to use the first one. Using objectForKey on currentLocal instance works.
NSString* lang = #"en_US";
NSLocale *currentLocal = [NSLocale autoupdatingCurrentLocale];
//get the localeIdentifier and create a new NSLocale.
id localIdentifier = [currentLocal objectForKey:NSLocaleIdentifier];
NSLocale *theLocal = [NSLocale localeWithLocaleIdentifier:localIdentifier];
NSLog(#"%#",[theLocal displayNameForKey:NSLocaleIdentifier
value:lang]
);

Answer 2

This is a known Apple issue for iOS 8.1 simulator only - not reproducible on 8.1 devices. See below issue description from Xcode 6.1 release notes:
Localization and Keyboard settings (including 3rd party keyboards) are
not correctly honored by Safari, Maps, and developer apps in the iOS
8.1 Simulator. [NSLocale currentLocale] returns en_US and only the English and Emoji keyboards are available. (18418630, 18512161).
See Xcode 6.1 Release Notes for more details.