iOS: Determine if device language is Right to Left (RTL)

Question

Is there a way to easily determine if the language the device is set to is right to left (RTL)?

Answer 1

Make sure you return the currently selected language, not the current region of the device. The region and language are often the same. However, if I am in North America and I set my language to Japanese, my region will still be English (United States). In order to check the character direction of the currently selected language, you can do:

+ (BOOL)isDeviceLanguageRTL {
  return ([NSLocale characterDirectionForLanguage:[[NSLocale preferredLanguages] objectAtIndex:0]] == NSLocaleLanguageDirectionRightToLeft);
}

You may likely want to cache the result, using dispatch_once.

Keep in mind that this is the user's preferred language direction, and not necessarily the language direction of the text. For that, use a C function that is based on u_charDirection.