Language

First please your json language in folder following your list language ./assets/locale/..

Then please check file ./lib/configs/language.dark and define your list language support

import 'package:flutter/material.dart';  
class AppLanguage {  
    ///Default Language  
    static Locale defaultLanguage = Locale("en");  

    ///List Language support in Application  
    static List<locale> supportLanguage = [  
        Locale("en"),  
        Locale("vi"),  
        Locale("ar"),  
        Locale("zh"),  
        Locale("ko"),  
        Locale("ja")  
    ];  

    ///Singleton factory  
    static final AppLanguage _instance = AppLanguage._internal();  

    factory AppLanguage() {  
        return _instance;  
    }  

    AppLanguage._internal();  
}

Open file  ./source/lib/utils/language.dart and add more full name from the json language files base on the language code

class UtilLanguage {
  ///Get Language Global Language Name
  static String getGlobalLanguageName(String code) {
    switch (code) {
      case 'en':
        return 'English';
      case 'vi':
        return 'Vietnamese';
      case 'ar':
        return 'Arabic';
      case 'da':
        return 'Danish';
      case 'de':
        return 'German';
      case 'el':
        return 'Greek';
      case 'fr':
        return 'French';
      case 'he':
        return 'Hebrew';
      case 'id':
        return 'Indonesian';
      case 'ja':
        return 'Japanese';
      case 'ko':
        return 'Korean';
      case 'lo':
        return 'Lao';
      case 'nl':
        return 'Dutch';
      case 'zh':
        return 'Chinese';
      case 'fa':
        return 'Iran';
      case 'km':
        return 'Cambodian';
      case 'pt':
        return 'Brazilian - Portuguese';
      case 'ru':
        return 'Russian';
      case 'tr':
        return 'Turkish';
      case 'hi':
        return 'Indian';

      default:
        return 'Unknown';
    }
  }

  static bool isRTL() {
    switch (AppLanguage.defaultLanguage.languageCode) {
      case "ar":
      case "he":
        return true;
      default:
        return false;
    }
  }

  ///Singleton factory
  static final UtilLanguage _instance = UtilLanguage._internal();

  factory UtilLanguage() {
    return _instance;
  }

  UtilLanguage._internal();
}

RTL Layout

You can define then language code will apply RTL layout from file  ./source/lib/utils/language.dart

static bool isRTL() {
    switch (AppLanguage.defaultLanguage.languageCode) {
      case "ar":
      case "he":
        return true;
      default:
        return false;
    }
  }