設定されている言語を取得する -カレントカルチャ- | Xamarin.Forms

2017/07/31
12:21

今回は、Xamarin.Formsでスマホに設定されている言語を取得または変更する機能についてご紹介いたします。前回の多言語化する記事が長くなっておりましたので、こちらに一部転載いたします。
CultureInfoクラスはPCLプロジェクトで使用可能ですが、取得または設定するメソッドが各デバイス毎に異なりますので、DependencyServiceで記述していきます。

前提条件
・Windows10 Pro 64Bit
・Visual Studio 2015 Community Update3
・Xamarin 4.3.0.795 (NuGet Xamarin.Forms 2.3.4.247)
・macOS Sierra 10.12.4 / Xcode8.3.1 / Xamarin.iOS 10.6.0.10

１．ＰＣＬの記述方法

DependencyServiceでカレントカルチャを取得する機能を実装します。
PCLプロジェクト内にDependencyServiceで呼び出すためのインターフェースを配置します。

ILocalizeService.cs

using System.Globalization;
namespace AppName.Services
{
    //DependencyServiceから利用する
    public interface ILocalizeService
    {
        CultureInfo GetCurrentCultureInfo();
        void SetLocale(CultureInfo ci);
    }
}

２．Androidの実装方法

Androidプロジェクト内に以下のクラスを配置します。

LocalizeService.cs

using System.Globalization;
using System.Threading;
using Xamarin.Forms;
using AppName.Droid.Services;
using AppName.Services;
using AppName.Library.Globalization;
[assembly: Dependency(typeof(LocalizeService))]
namespace AppName.Droid.Services
{
    public class LocalizeService : ILocalizeService
    {
        public void SetLocale(CultureInfo ci)
        {
            Thread.CurrentThread.CurrentCulture = ci;
            Thread.CurrentThread.CurrentUICulture = ci;
        }
        public CultureInfo GetCurrentCultureInfo()
        {
            var netLanguage = "en";
            var androidLocale = Java.Util.Locale.Default;
            netLanguage = AndroidToDotnetLanguage(androidLocale.ToString().Replace("_", "-"));
            // this gets called a lot - try/catch can be expensive so consider caching or something
            System.Globalization.CultureInfo ci = null;
            try
            {
                ci = new System.Globalization.CultureInfo(netLanguage);
            }
            catch (CultureNotFoundException)
            {
                // iOS locale not valid .NET culture (eg. "en-ES" : English in Spain)
                // fallback to first characters, in this case "en"
                try
                {
                    var fallback = ToDotnetFallbackLanguage(new PlatformCulture(netLanguage));
                    ci = new System.Globalization.CultureInfo(fallback);
                }
                catch (CultureNotFoundException)
                {
                    // iOS language not valid .NET culture, falling back to English
                    ci = new System.Globalization.CultureInfo("en");
                }
            }
            return ci;
        }
        string AndroidToDotnetLanguage(string androidLanguage)
        {
            var netLanguage = androidLanguage;
            //certain languages need to be converted to CultureInfo equivalent
            switch (androidLanguage)
            {
                case "ms-BN":   // "Malaysian (Brunei)" not supported .NET culture
                case "ms-MY":   // "Malaysian (Malaysia)" not supported .NET culture
                case "ms-SG":   // "Malaysian (Singapore)" not supported .NET culture
                    netLanguage = "ms"; // closest supported
                    break;
                case "in-ID":  // "Indonesian (Indonesia)" has different code in  .NET
                    netLanguage = "id-ID"; // correct code for .NET
                    break;
                case "gsw-CH":  // "Schwiizertüütsch (Swiss German)" not supported .NET culture
                    netLanguage = "de-CH"; // closest supported
                    break;
                    // add more application-specific cases here (if required)
                    // ONLY use cultures that have been tested and known to work
                
                default:
                    //2019/01/11 中国語の対応
                    //zh-HK-#Hant
                    //zh-TW-#Hant
                    //zh-CN-#Hans
                    if (androidLanguage.StartsWith("zh-"))
                    {
                        if (androidLanguage.Contains("Hant"))
                        {
                            netLanguage = "zh-Hant";
                        }
                        else if (androidLanguage.Contains("Hans"))
                        {
                            netLanguage = "zh-Hans";
                        }
                    }
                    break;
            }
            return netLanguage;
        }
        string ToDotnetFallbackLanguage(PlatformCulture platCulture)
        {
            var netLanguage = platCulture.LanguageCode; // use the first part of the identifier (two chars, usually);
            switch (platCulture.LanguageCode)
            {
                case "gsw":
                    netLanguage = "de-CH"; // equivalent to German (Switzerland) for this app
                    break;
                    // add more application-specific cases here (if required)
                    // ONLY use cultures that have been tested and known to work
            }
            return netLanguage;
        }
    }
}

2019/01/12追記
Android7 以降において、中国語（簡体語・繁体語）の取得が正しくできない問題を修正しました。

３．iOSの実装方法

iOSプロジェクト内に以下のクラスを配置します。

LocalizeService.cs

using System.Globalization;
using System.Threading;
using Foundation;
using Xamarin.Forms;
using AppName.iOS.Services;
using AppName.Services;
using AppName.Library.Globalization;
[assembly: Dependency(typeof(LocalizeService))]
namespace AppName.iOS.Services
{
    public class LocalizeService : ILocalizeService
    {
        public void SetLocale(CultureInfo ci)
        {
            Thread.CurrentThread.CurrentCulture = ci;
            Thread.CurrentThread.CurrentUICulture = ci;
        }
        public CultureInfo GetCurrentCultureInfo()
        {
            var netLanguage = "en";
            if (NSLocale.PreferredLanguages.Length > 0)
            {
                var pref = NSLocale.PreferredLanguages[0];
                netLanguage = iOSToDotnetLanguage(pref);
            }
            // this gets called a lot - try/catch can be expensive so consider caching or something
            System.Globalization.CultureInfo ci = null;
            try
            {
                ci = new System.Globalization.CultureInfo(netLanguage);
            }
            catch (CultureNotFoundException)
            {
                // iOS locale not valid .NET culture (eg. "en-ES" : English in Spain)
                // fallback to first characters, in this case "en"
                try
                {
                    var fallback = ToDotnetFallbackLanguage(new PlatformCulture(netLanguage));
                    ci = new System.Globalization.CultureInfo(fallback);
                }
                catch (CultureNotFoundException)
                {
                    // iOS language not valid .NET culture, falling back to English
                    ci = new System.Globalization.CultureInfo("en");
                }
            }
            return ci;
        }
        string iOSToDotnetLanguage(string iOSLanguage)
        {
            //中国語が正しく取れていない不具合を修正 
            if (iOSLanguage.ToLower().Contains("zh-han"))
            {
                iOSLanguage = iOSLanguage.Substring(iOSLanguage.ToLower().IndexOf("zh-han"), 7);
            }

            var netLanguage = iOSLanguage;
            //certain languages need to be converted to CultureInfo equivalent
            switch (iOSLanguage)
            {
                case "ms-MY":   // "Malaysian (Malaysia)" not supported .NET culture
                case "ms-SG":   // "Malaysian (Singapore)" not supported .NET culture
                    netLanguage = "ms"; // closest supported
                    break;
                case "gsw-CH":  // "Schwiizertüütsch (Swiss German)" not supported .NET culture
                    netLanguage = "de-CH"; // closest supported
                    break;
                    // add more application-specific cases here (if required)
                    // ONLY use cultures that have been tested and known to work
            }
            return netLanguage;
        }
        string ToDotnetFallbackLanguage(PlatformCulture platCulture)
        {
            var netLanguage = platCulture.LanguageCode; // use the first part of the identifier (two chars, usually);
            switch (platCulture.LanguageCode)
            {
                case "pt":
                    netLanguage = "pt-PT"; // fallback to Portuguese (Portugal)
                    break;
                case "gsw":
                    netLanguage = "de-CH"; // equivalent to German (Switzerland) for this app
                    break;
                    // add more application-specific cases here (if required)
                    // ONLY use cultures that have been tested and known to work
            }
            return netLanguage;
        }
    }
}

４．使用方法

PCLプロジェクトの中の任意のページに記述します。

TestPage.xaml.cs

using AppName.Services;
using Xamarin.Forms;
public class TestPage : ContentPage
{
    void OnButtonClick(object sender, EventArgs e)
    {
        CultureInfo culture = DependencyService.Get<ILocalizeService>().GetCurrentCultureInfo()
    }
}

最後までお読みいただきありがとうございます。
当ブログの内容をまとめた Xamarin逆引きメニューは以下のURLからご覧になれます。
https://itblog.dynaspo.com/blog-entry-81.html

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