Fix Chinese locales once and for all (up to Nougat)

Seriously fix #927. From now on it will work even in Hong Kong (`/^zh-Han[st]-HK$/`) where for some reason people use Simplified Chinese and Traditional Chinese at the same time.

build.sbt

@@ -22,7 +22,7 @@ shrinkResources in Android := true
 
 typedResources in Android := false
 
-resConfigs in Android := Seq("ru", "zh", "zh-rCN")
+resConfigs in Android := Seq("ru", "zh-rCN", "zh-rTW")
 
 dexMaxHeap in Android := "4g"
 

src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala

@@ -40,13 +40,16 @@
 package com.github.shadowsocks
 
 import java.util
+import java.util.Locale
 import java.util.concurrent.TimeUnit
 
 import android.app.Application
+import android.content.res.Configuration
+import android.os.{Build, LocaleList}
 import android.preference.PreferenceManager
 import android.support.v7.app.AppCompatDelegate
 import com.github.shadowsocks.database.{DBHelper, ProfileManager}
-import com.github.shadowsocks.utils.{Key, Utils, TcpFastOpen}
+import com.github.shadowsocks.utils.{Key, TcpFastOpen, Utils}
 import com.google.android.gms.analytics.{GoogleAnalytics, HitBuilders, StandardExceptionParser}
 import com.google.android.gms.common.api.ResultCallback
 import com.google.android.gms.tagmanager.{ContainerHolder, TagManager}
@@ -54,6 +57,9 @@ import com.j256.ormlite.logger.LocalLog
 
 object ShadowsocksApplication {
   var app: ShadowsocksApplication = _
+
+  private final lazy val SIMPLIFIED_CHINESE = Locale.forLanguageTag("zh-Hans-CN")
+  private final lazy val TRADITIONAL_CHINESE = Locale.forLanguageTag("zh-Hant-TW")
 }
 
 class ShadowsocksApplication extends Application {
@@ -88,10 +94,52 @@ class ShadowsocksApplication extends Application {
     profileManager.getProfile(id) getOrElse profileManager.createProfile()
   }
 
+  private def checkChineseLocale(locale: Locale): Locale = if (locale.getLanguage == "zh") locale.getCountry match {
+    case "CN" | "TW" => null            // already supported
+    case _ => locale.getScript match {  // fallback to the corresponding script
+      case "Hans" => SIMPLIFIED_CHINESE
+      case "Hant" => TRADITIONAL_CHINESE
+    }
+  } else null
+
+  private def checkChineseLocale(config: Configuration): Unit = if (Build.VERSION.SDK_INT >= 24) {
+    val localeList = config.getLocales
+    val newList = new Array[Locale](localeList.size())
+    var changed = false
+    for (i <- 0 until localeList.size()) {
+      val locale = localeList.get(i)
+      val newLocale = checkChineseLocale(locale)
+      if (newLocale == null) newList(i) = locale else {
+        newList(i) = newLocale
+        changed = true
+      }
+    }
+    if (changed) {
+      val newConfig = new Configuration(config)
+      newConfig.setLocales(new LocaleList(newList.distinct: _*))
+      val res = getResources
+      res.updateConfiguration(newConfig, res.getDisplayMetrics)
+    }
+  } else {
+    val newLocale = checkChineseLocale(config.locale)
+    if (config.locale != newLocale) {
+      val newConfig = new Configuration(config)
+      newConfig.locale = newLocale
+      val res = getResources
+      res.updateConfiguration(newConfig, res.getDisplayMetrics)
+    }
+  }
+
+  override def onConfigurationChanged(newConfig: Configuration) {
+    super.onConfigurationChanged(newConfig)
+    checkChineseLocale(newConfig)
+  }
+
   override def onCreate() {
-    if (!BuildConfig.DEBUG) java.lang.System.setProperty(LocalLog.LOCAL_LOG_LEVEL_PROPERTY, "ERROR")
     app = this
+    if (!BuildConfig.DEBUG) java.lang.System.setProperty(LocalLog.LOCAL_LOG_LEVEL_PROPERTY, "ERROR")
     AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)
+    checkChineseLocale(getResources.getConfiguration)
     val tm = TagManager.getInstance(this)
     val pending = tm.loadContainerPreferNonDefault("GTM-NT8WS8", R.raw.gtm_default_container)
     val callback = new ResultCallback[ContainerHolder] {