在Swift 4.2和Xcode 10.1中

let language = NSLocale.preferredLanguages[0]
debugPrint(language)//en

在Swift 5.x中

let langStr = Locale.current.languageCode
debugPrint(langStr ?? "") //en  el

I actually misread the original question, thought it asked for the "app UI" language (that's what I had googled for), not the "device UI", in which case the best answers would be the ones using preferredLocalizations, but those answers still give you a code, there is one more step to get a nice string to display. So, while the "device UI" language is already answered, if you want to display a nice string for which of the UI languages you support is currently in use, obviously the simplest solution is:

NSLocalizedString(@"currentLanguage", @"")

在你的每一个UI本地化中你都指定了你想要的显示方式。例如，在你的。strings文件的en版本中，你会有:

"currentLanguage"="English";

在你的fr版本的.strings文件中，你会有:

"currentLanguage"="Francais";

等。不要混淆代码等，你可以让你自己的字符串很好地匹配你的UI。

我试图为自己找出正确的解决办法。当我使用Locale.preferredLanguages.first从你的应用程序设置返回首选语言。

如果你想从用户设备设置中了解语言，你应该使用下面的字符串:

斯威夫特3

let currentDeviceLanguage = Locale.current.languageCode
// Will return the optional String

要展开并使用，请看下面这行:

if let currentDeviceLanguage = Locale.current.languageCode {
    print("currentLanguage", currentDeviceLanguage)

    // For example
    if currentDeviceLanguage == "he" {
        UIView.appearance().semanticContentAttribute = .forceRightToLeft
    } else {
        UIView.appearance().semanticContentAttribute = .forceLeftToRight
    }
}

SWIFT-4

 // To get device default selected language. It will print like short name of zone. For english, en or spain, es.

let language = Bundle.main.preferredLocalizations.first! as NSString
print("device language",language)

iOS13, Swift 5+

Locale.preferredLanguages.first

iOS 9的解决方案:

NSString *language = [[NSLocale preferredLanguages] objectAtIndex:0];

language = "en-US"

NSDictionary *languageDic = [NSLocale componentsFromLocaleIdentifier:language];

languageDic将拥有所需的组件

NSString *countryCode = [languageDic objectForKey:@"kCFLocaleCountryCodeKey"];

countryCode = "US"

NSString *languageCode = [languageDic objectForKey:@"kCFLocaleLanguageCodeKey"];

密码:

对于Swift 3:

NSLocale。preferredLanguages[0]作为字符串