[swift] How to get current language code with Swift?

I want get the language code of the device (en, es...) in my app written with Swift. How can get this?

I'm trying this:

var preferredLanguages : NSLocale!
let pre = preferredLanguages.displayNameForKey(NSLocaleIdentifier, value: preferredLanguages)

But this returns nil.

In Swift 3:

NSLocale.current.languageCode

Locale.current.languageCode returns me wrong code, so I use these extensions:

extension Locale {
    static var preferredLanguageCode: String {
        let defaultLanguage = "en"
        let preferredLanguage = preferredLanguages.first ?? defaultLanguage
        return Locale(identifier: preferredLanguage).languageCode ?? defaultLanguage
    }

    static var preferredLanguageCodes: [String] {
        return Locale.preferredLanguages.compactMap({Locale(identifier: $0).languageCode})
    }
}

This is what I use in Swift 5 Xcode 11:

Inside the class variables:

let languagePrefix = Bundle.main.preferredLocalizations.first?.prefix(2)

This comes as a string. It returns 2 characters, i.e. "en", "es", "de"...

From this I can easily determine what language to display:

 if languagePrefix == "es" { self.flipCard.setTitle("última carta", for: .normal) }
 if languagePrefix == "en" { self.flipCard.setTitle("Last Card", for: .normal) }

If you want the full information of the language, then remove ?.prefex(2)

Swift 5.3:

let languagePrefix = Locale.preferredLanguages[0]
print(languagePrefix)

In Swift 3

let langStr = Locale.current.languageCode

Swift 3 & 4 & 4.2 & 5

Locale.current.languageCode does not compile regularly. Because you did not implemented localization for your project.

You have two possible solutions

1) String(Locale.preferredLanguages[0].prefix(2)) It returns phone lang properly.

If you want to get the type en-En, you can use Locale.preferredLanguages[0]

2) Select Project(MyApp)->Project (not Target)-> press + button into Localizations, then add language which you want.

I want to track the language chosen by the user in Settings app every time the user launches my app - that is not yet localized (my app is in English only). I adopted this logic:

1. create an enum to to make it easier to handle the languages in array

   enum Language: String {
   
   case none = ""
   case en = "English"
   case fr = "French"
   case it = "Italian"
   
   } // add as many languages you want
   

2. create a couple of extension to Locale

   extension Locale {
   
       static var enLocale: Locale {
   
           return Locale(identifier: "en-EN")
       } // to use in **currentLanguage** to get the localizedString in English
   
       static var currentLanguage: Language? {
   
           guard let code = preferredLanguages.first?.components(separatedBy: "-").last else {
   
               print("could not detect language code")
   
               return nil
           }
   
           guard let rawValue = enLocale.localizedString(forLanguageCode: code) else {
   
               print("could not localize language code")
   
               return nil
           }
   
           guard let language = Language(rawValue: rawValue) else {
   
               print("could not init language from raw value")
   
               return nil
           }
           print("language: \(code)-\(rawValue)")
   
           return language
       }
   }
   

3. When you need, you can simply use the extension

   if let currentLanguage = Locale.currentLanguage {
       print(currentLanguage.rawValue)
       // Your code here.
   }
   

you may use the below code it works fine with swift 3

var preferredLanguage : String = Bundle.main.preferredLocalizations.first!

To get current language used in your app (different than preferred languages)

NSLocale.currentLocale().objectForKey(NSLocaleLanguageCode)!

In Swift, You can get the locale using.

let locale = Locale.current.identifier

Swift 4 & 5:

Locale.current.languageCode

It's important to make the difference between the App language and the device locale language (The code below is in Swift 3)

Will return the Device language:

let locale = NSLocale.current.languageCode

Will return the App language:

let pre = Locale.preferredLanguages[0]

swift 3

let preferredLanguage = Locale.preferredLanguages[0] as String
print (preferredLanguage) //en-US

let arr = preferredLanguage.components(separatedBy: "-")
let deviceLanguage = arr.first
print (deviceLanguage) //en