如何在Android API中獲取IETF BCP47語言代碼<21

Question

有沒有一種巧妙的方法可以在android中爲API獲取BCP47語言代碼小於21？在API級別21+中，Locale.toLanguageTag正是我所需要的。你如何在較低的API級別獲得這個？

Answer 1

Apache Cordova的好人爲此開發了一個解決方案，如here所示。

我修改那裏代碼到下述溶液：

/** 
* Modified from: 
* https://github.com/apache/cordova-plugin-globalization/blob/master/src/android/Globalization.java 
* 
* Returns a well-formed ITEF BCP 47 language tag representing this locale string 
* identifier for the client's current locale 
* 
* @return String: The BCP 47 language tag for the current locale 
*/ 
public static String toBcp47Language(Locale loc) { 
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { 
     return loc.toLanguageTag(); 
    } 

    // we will use a dash as per BCP 47 
    final char SEP = '-'; 
    String language = loc.getLanguage(); 
    String region = loc.getCountry(); 
    String variant = loc.getVariant(); 

    // special case for Norwegian Nynorsk since "NY" cannot be a variant as per BCP 47 
    // this goes before the string matching since "NY" wont pass the variant checks 
    if (language.equals("no") && region.equals("NO") && variant.equals("NY")) { 
     language = "nn"; 
     region = "NO"; 
     variant = ""; 
    } 

    if (language.isEmpty() || !language.matches("\\p{Alpha}{2,8}")) { 
     language = "und";  // Follow the Locale#toLanguageTag() implementation 
     // which says to return "und" for Undetermined 
    } else if (language.equals("iw")) { 
     language = "he";  // correct deprecated "Hebrew" 
    } else if (language.equals("in")) { 
     language = "id";  // correct deprecated "Indonesian" 
    } else if (language.equals("ji")) { 
     language = "yi";  // correct deprecated "Yiddish" 
    } 

    // ensure valid country code, if not well formed, it's omitted 
    if (!region.matches("\\p{Alpha}{2}|\\p{Digit}{3}")) { 
     region = ""; 
    } 

    // variant subtags that begin with a letter must be at least 5 characters long 
    if (!variant.matches("\\p{Alnum}{5,8}|\\p{Digit}\\p{Alnum}{3}")) { 
     variant = ""; 
    } 

    StringBuilder bcp47Tag = new StringBuilder(language); 
    if (!region.isEmpty()) { 
     bcp47Tag.append(SEP).append(region); 
    } 
    if (!variant.isEmpty()) { 
     bcp47Tag.append(SEP).append(variant); 
    } 

    return bcp47Tag.toString(); 
}