public class LocalUtils {

    private static final String LANGUAGE_CODE_ENGLISH = "en";


    // returns application language eg: en || fa ...
    public static String getAppLanguage() {
        return Locale.getDefault().getLanguage();
    }

    // returns device language eg: en || fa ...
    public static String getDeviceLanguage() {
        return ConfigurationCompat.getLocales(Resources.getSystem().getConfiguration()).get(0).getLanguage();
    }

    public static boolean isDeviceEnglish() {
        return getDeviceLanguage().equals(new Locale(LANGUAGE_CODE_ENGLISH).getLanguage());
    }

    public static boolean isAppEnglish() {
        return getAppLanguage().equals(new Locale(LANGUAGE_CODE_ENGLISH).getLanguage());
    }


}

Log.i("AppLanguage: ",     LocalUtils.getAppLanguage());
Log.i("DeviceLanguage: ",  LocalUtils.getDeviceLanguage());
Log.i("isDeviceEnglish: ", String.valueOf(LocalUtils.isDeviceEnglish()));
Log.i("isAppEnglish: ",    String.valueOf(LocalUtils.isAppEnglish()));

如果你想要获得你的设备所选择的语言，这可能会帮助你:

Locale.getDefault().getDisplayLanguage();

你可以使用Locale.getDefault().getLanguage();要获得常用的语言代码(例如:“德”、“en”)

你可以尝试从系统资源中获取locale:

PackageManager packageManager = context.getPackageManager();
Resources resources = packageManager.getResourcesForApplication("android");
String language = resources.getConfiguration().locale.getLanguage();

您可以从当前区域“提取”语言。你可以通过标准的Java API或者使用Android Context来提取语言环境。例如，下面这两行是等价的:

String locale = context.getResources().getConfiguration().locale.getDisplayName();
String locale = java.util.Locale.getDefault().getDisplayName();

我检查了我的Android 4.1.2设备上的Locale方法，结果是:

Locale.getDefault().getLanguage()       ---> en      
Locale.getDefault().getISO3Language()   ---> eng 
Locale.getDefault().getCountry()        ---> US 
Locale.getDefault().getISO3Country()    ---> USA 
Locale.getDefault().getDisplayCountry() ---> United States 
Locale.getDefault().getDisplayName()    ---> English (United States) 
Locale.getDefault().toString()          ---> en_US
Locale.getDefault().getDisplayLanguage()---> English
Locale.getDefault().toLanguageTag()     ---> en-US

如果API级别为24或以上，则使用LocaleList.getDefault().get(0).getLanguage() 否则使用Locale.getDefault.getLanguage()

private fun getSystemLocale() = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    LocaleList.getDefault().get(0).language
} else {
    Locale.getDefault().language
}

参考:https://developer.android.com/guide/topics/resources/multilingual-support