add basic multiple language support

app/src/main/java/com/github/kr328/clash/BaseActivity.kt

@@ -20,6 +20,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.launch
+import java.util.*
 
 abstract class BaseActivity : AppCompatActivity(), CoroutineScope by MainScope() {
     class EmptyBroadcastReceiver : BroadcastReceiver() {
@@ -55,6 +56,7 @@ abstract class BaseActivity : AppCompatActivity(), CoroutineScope by MainScope()
     var menu: Menu? = null
     lateinit var uiPreference: UiPreferences
         private set
+    lateinit var language: String
 
     open suspend fun onClashStarted() {}
     open suspend fun onClashStopped(reason: String?) {}
@@ -81,17 +83,40 @@ abstract class BaseActivity : AppCompatActivity(), CoroutineScope by MainScope()
         super.setContentView(base)
     }
 
+    override fun attachBaseContext(newBase: Context?) {
+        val base = newBase ?: return super.attachBaseContext(newBase)
+
+        uiPreference = UiPreferences(base)
+
+        language = uiPreference.get(UiPreferences.LANGUAGE)
+
+        val languageOverride = language.split("-")
+        if ( language.isEmpty() )
+            return super.attachBaseContext(base)
+
+        val configuration = base.resources.configuration
+        val localeOverride = if ( languageOverride.size == 2 )
+            Locale(languageOverride[0], languageOverride[1])
+        else
+            Locale(languageOverride[0])
+
+        configuration.setLocale(localeOverride)
+
+        super.attachBaseContext(base.createConfigurationContext(configuration))
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
-        uiPreference = UiPreferences(this)
-
         resetLightNavigationBar()
     }
 
     override fun onStart() {
         super.onStart()
 
+        if ( language != uiPreference.get(UiPreferences.LANGUAGE) )
+            recreate()
+
         Broadcasts.register(receiver)
     }
 

app/src/main/java/com/github/kr328/clash/preference/UiPreferences.kt

@@ -11,10 +11,15 @@ class UiPreferences(context: Context) {
         const val PROXY_SORT_NAME = "name"
         const val PROXY_SORT_DELAY = "delay"
 
+        const val LANGUAGE_DEFAULT = ""
+        const val LANGUAGE_EN = "en"
+        const val LANGUAGE_ZH_CN = "zh-CN"
+
         val PROXY_GROUP_SORT = StringEntry("proxy_group_sort", PROXY_SORT_DEFAULT)
         val PROXY_PROXY_SORT = StringEntry("proxy_proxy_sort", PROXY_SORT_DEFAULT)
         val PROXY_LAST_SELECT_GROUP = StringEntry("proxy_last_select_group", "")
         val PROXY_MERGE_PREFIX = BooleanEntry("proxy_merge_prefix", true)
+        val LANGUAGE = StringEntry("language", "")
     }
 
     interface Entry<T> {
@@ -22,7 +27,7 @@ class UiPreferences(context: Context) {
         fun put(editor: SharedPreferences.Editor, value: T)
     }
 
-    class StringEntry(private val key: String, private val defaultValue: String? = null) :
+    class StringEntry(private val key: String, private val defaultValue: String) :
         Entry<String> {
         override fun get(sharedPreferences: SharedPreferences): String {
             return sharedPreferences.getString(key, defaultValue)!!

app/src/main/res/layout/activity_main.xml

@@ -20,10 +20,9 @@
             android:gravity="center_vertical">
 
             <View
-                android:layout_width="50dp"
-                android:layout_height="50dp"
-                android:layout_marginStart="36dp"
-                android:contentDescription="@string/application_name"
+                android:layout_width="35dp"
+                android:layout_height="35dp"
+                android:layout_marginStart="40dp"
                 android:background="@drawable/ic_logo" />
 
             <TextView
@@ -33,7 +32,7 @@
                 android:textColor="?attr/colorPrimary"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_marginStart="15dp" />
+                android:layout_marginStart="25dp" />
         </LinearLayout>
 
         <com.github.kr328.clash.design.view.ColorfulTextCard