changed icon and added system default setting

app/src/main/java/com/github/libretube/MainActivity.kt

@@ -42,9 +42,13 @@ class MainActivity : AppCompatActivity() {
         RetrofitInstance.url = sharedPreferences.getString("instance", "https://pipedapi.kavin.rocks/")!!
         DynamicColors.applyToActivitiesIfAvailable(application)
         setContentView(R.layout.activity_main)
-        var languageName = sharedPreferences.getString("language", "en")!!
+        val languageName = sharedPreferences.getString("language", "sys")
         if (languageName != "") {
-            val locale = Locale(languageName)
+            var locale = if (languageName != "sys") {
+                Locale(languageName)
+            } else {
+                Locale.getDefault()
+            }
             val res = resources
             val dm = res.displayMetrics
             val conf = res.configuration

app/src/main/res/drawable/ic_flag.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorControlNormal">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M14.4,6L14,4H5v17h2v-7h5.6l0.4,2h7V6z"/>
+</vector>

app/src/main/res/values/array.xml

@@ -406,6 +406,7 @@
     </string-array>
 
     <string-array name="languages">
+        <item>@string/systemLanguage</item>
         <item>Arabic</item>
         <item>Czech</item>
         <item>English</item>
@@ -428,6 +429,7 @@
     </string-array>
 
     <string-array name="languagesValue">
+        <item>sys</item>
         <item>ar</item>
         <item>cs</item>
         <item>en</item>

app/src/main/res/values/strings.xml

@@ -54,4 +54,5 @@
     <string name="fail">Failed :(</string>
     <string name="about">About</string>
     <string name="changeLanguage">Change Language</string>
+    <string name="systemLanguage">System Language</string>
 </resources>

app/src/main/res/xml/settings.xml

@@ -8,7 +8,7 @@
         app:entryValues="@array/regionsValue"
         app:defaultValue="US"
         app:useSimpleSummaryProvider="true"
-        android:icon="@drawable/ic_language"
+        android:icon="@drawable/ic_region"
         />
 
     <ListPreference
@@ -16,9 +16,9 @@
         app:title="@string/changeLanguage"
         app:entries="@array/languages"
         app:entryValues="@array/languagesValue"
-        app:defaultValue="en"
+        app:defaultValue="sys"
         app:useSimpleSummaryProvider="true"
-        android:icon="@drawable/ic_language"
+        android:icon="@drawable/ic_flag"
         />
 
     <ListPreference