feature: multi-language supported

Pixiview/Resources/Languages/zh-CN.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<root>
+    <Follow>已关注</Follow>
+</root>

Pixiview/Resources/PlatformCulture.cs

@@ -0,0 +1,43 @@
+namespace Pixiview.Resources
+{
+    public class PlatformCulture
+    {
+        public string PlatformString { get; private set; }
+        public string LanguageCode { get; private set; }
+        public string LocaleCode { get; private set; }
+
+        public string Language
+        {
+            get { return string.IsNullOrEmpty(LocaleCode) ? LanguageCode : LanguageCode + "-" + LocaleCode; }
+        }
+
+        public PlatformCulture() : this(null) { }
+        public PlatformCulture(string cultureString)
+        {
+            if (string.IsNullOrEmpty(cultureString))
+            {
+                //throw new ArgumentNullException(nameof(cultureString), "Expected culture identieifer");
+                cultureString = "en";
+            }
+
+            PlatformString = cultureString.Replace('_', '-');
+            var index = PlatformString.IndexOf('-');
+            if (index > 0)
+            {
+                var parts = PlatformString.Split('-');
+                LanguageCode = parts[0];
+                LocaleCode = parts[parts.Length - 1];
+            }
+            else
+            {
+                LanguageCode = PlatformString;
+                LocaleCode = "";
+            }
+        }
+
+        public override string ToString()
+        {
+            return PlatformString;
+        }
+    }
+}

Pixiview/Resources/ResourceHelper.cs

@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Xml.Linq;
+using Xamarin.Forms;
+using Xamarin.Forms.Xaml;
+
+namespace Pixiview.Resources
+{
+    public class ResourceHelper
+    {
+        static readonly Dictionary<string, LanguageResource> dict = new Dictionary<string, LanguageResource>();
+
+        public static string GetResource(string name, params object[] args)
+        {
+            if (!dict.TryGetValue(App.CurrentCulture.PlatformString, out LanguageResource lang))
+            {
+                lang = new LanguageResource(App.CurrentCulture);
+                dict.Add(App.CurrentCulture.PlatformString, lang);
+            }
+
+            if (args == null || args.Length == 0)
+            {
+                return lang[name];
+            }
+            return string.Format(lang[name], args);
+        }
+
+        private class LanguageResource
+        {
+            private readonly Dictionary<string, string> strings;
+
+            public string this[string key]
+            {
+                get
+                {
+                    if (strings != null && strings.TryGetValue(key, out string val))
+                    {
+                        return val;
+                    }
+                    return key;
+                }
+            }
+
+            public LanguageResource(PlatformCulture lang)
+            {
+                try
+                {
+                    var assembly = IntrospectionExtensions.GetTypeInfo(typeof(LanguageResource)).Assembly;
+                    var names = assembly.GetManifestResourceNames();
+                    var name = names.FirstOrDefault(n
+                        => string.Equals(n, $"Pixiview.Resources.Languages.{lang.Language}.xml", StringComparison.OrdinalIgnoreCase)
+                        || string.Equals(n, $"Pixiview.Resources.Languages.{lang.LanguageCode}.xml", StringComparison.OrdinalIgnoreCase));
+                    if (name == null)
+                    {
+                        name = "Pixiview.Resources.Languages.zh-CN.xml";
+                    }
+                    XDocument xml;
+                    using (var stream = assembly.GetManifestResourceStream(name))
+                    {
+                        xml = XDocument.Load(stream);
+                    }
+                    strings = new Dictionary<string, string>();
+                    foreach (var ele in xml.Root.Elements())
+                    {
+                        strings[ele.Name.LocalName] = ele.Value;
+                    }
+                }
+                catch
+                {
+                    // load failed
+                }
+            }
+        }
+    }
+
+    [ContentProperty(nameof(Text))]
+    public class TextExtension : IMarkupExtension
+    {
+        public string Text { get; set; }
+
+        public object ProvideValue(IServiceProvider serviceProvider)
+        {
+            if (Text == null)
+            {
+                return string.Empty;
+            }
+            return ResourceHelper.GetResource(Text);
+        }
+    }
+}