Handle preferred languages on android

android/build.gradle

@@ -1,33 +1,18 @@
-buildscript {
-    repositories {
-        jcenter()
-    }
-
-    dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.3'
-    }
-}
-
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 23
-    buildToolsVersion "23.0.1"
+    compileSdkVersion 25
+    buildToolsVersion "25.0.2"
 
     defaultConfig {
         minSdkVersion 16
         targetSdkVersion 22
         versionCode 1
         versionName "1.0"
+        ndk {
+            abiFilters "armeabi-v7a", "x86"
+        }
     }
-
-    lintOptions {
-        abortOnError false
-    }
-}
-
-repositories {
-    mavenCentral()
 }
 
 dependencies {

android/src/main/java/com/alexanderzaytsev/rn18n/RNI18nModule.java

@@ -1,15 +1,17 @@
 package com.alexanderzaytsev.rn18n;
 
 import android.os.Build;
+import android.os.LocaleList;
 
+import com.facebook.react.bridge.Arguments;
+import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.module.annotations.ReactModule;
 
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 
-@ReactModule(name = "RNI18n")
 public class RNI18nModule extends ReactContextBaseJavaModule {
 
   public RNI18nModule(ReactApplicationContext reactContext) {
@@ -21,21 +23,27 @@ public class RNI18nModule extends ReactContextBaseJavaModule {
     return "RNI18n";
   }
 
-  private String getCurrentLocale() {
-    Locale currentLocale = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
-      ? getReactApplicationContext().getResources().getConfiguration().getLocales().get(0)
-      : getReactApplicationContext().getResources().getConfiguration().locale;
+  private boolean isSupportingPreferredLanguages() {
+    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N;
+  }
 
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
-      return currentLocale.toLanguageTag();
+  private LocaleList getLocales() {
+    return this.isSupportingPreferredLanguages()
+      ? getReactApplicationContext().getResources().getConfiguration().getLocales()
+      : new LocaleList(getReactApplicationContext().getResources().getConfiguration().locale);
+  }
+
+  private String toLanguageTag(Locale locale) {
+    if (this.isSupportingPreferredLanguages()) {
+      return locale.toLanguageTag();
     }
 
     StringBuilder builder = new StringBuilder();
-    builder.append(currentLocale.getLanguage());
+    builder.append(locale.getLanguage());
 
-    if (currentLocale.getCountry() != null) {
+    if (locale.getCountry() != null) {
       builder.append("-");
-      builder.append(currentLocale.getCountry());
+      builder.append(locale.getCountry());
     }
 
     return builder.toString();
@@ -44,7 +52,16 @@ public class RNI18nModule extends ReactContextBaseJavaModule {
   @Override
   public Map<String, Object> getConstants() {
     HashMap<String,Object> constants = new HashMap<String,Object>();
-    constants.put("locale", this.getCurrentLocale());
+    LocaleList locales = this.getLocales();
+    WritableArray languages = Arguments.createArray();
+
+    for (int i = 0; i < locales.size(); i++) {
+      languages.pushString(this.toLanguageTag(locales.get(i)));
+    }
+
+    constants.put("language", languages.getString(0));
+    constants.put("languages", languages);
+
     return constants;
   }
 }

android/src/main/res/values/styles.xml

@@ -0,0 +1,8 @@
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
+        <!-- Customize your theme here. -->
+    </style>
+
+</resources>