App localization and language controller addition

lang/en.json

@@ -0,0 +1,3 @@
+{
+    "hello-world": "Hello World"
+}

lang/es.json

@@ -0,0 +1,3 @@
+{
+    "hello-world": "Hola Mundo"
+}

lang/fr.json

@@ -0,0 +1,3 @@
+{
+    "hello-world": "Bonjour le monde"
+}

lang/hi.json

@@ -0,0 +1,3 @@
+{
+    "hello-world": "नमस्ते दुनिया"
+}

lang/zh-CN.json

@@ -0,0 +1,3 @@
+{
+    "hello-world": "你好"
+}

lib/controllers/lang_controller.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class AppLanguage extends ChangeNotifier {
+  Locale _appLocale = const Locale('en');
+
+  Locale get appLocal => _appLocale ?? const Locale("en");
+  fetchLocale() async {
+    final prefs = await SharedPreferences.getInstance();
+    if (prefs.getString('language_code') == null) {
+      _appLocale = const Locale('en');
+      return Null;
+    }
+    _appLocale = Locale(prefs.getString('language_code'));
+    return Null;
+  }
+
+  Future<void> changeLanguage(Locale type) async {
+    final prefs = await SharedPreferences.getInstance();
+    if (_appLocale == type) {
+      return;
+    }
+
+    if (type == const Locale("es")) {
+      //If selected language is spanish
+      _appLocale = const Locale("es");
+      await prefs.setString('language_code', 'es');
+      await prefs.setString('countryCode', 'ES');
+    } else if (type == const Locale("fr")) {
+      //If selected language is french
+      _appLocale = const Locale("fr");
+      await prefs.setString('language_code', 'fr');
+      await prefs.setString('countryCode', 'FR');
+    } else if (type == const Locale("hi")) {
+      //If selected language is hindi
+      _appLocale = const Locale("hi");
+      await prefs.setString('language_code', 'hi');
+      await prefs.setString('countryCode', 'IN');
+    } else if (type == const Locale("zh-CN")) {
+      //If selected language is Chinese
+      _appLocale = const Locale("zh-CN");
+      await prefs.setString('language_code', 'zh-CN');
+      await prefs.setString('countryCode', 'CN');
+    } else {
+      //If selected language is english
+      _appLocale = const Locale("en");
+      await prefs.setString('language_code', 'en');
+      await prefs.setString('countryCode', 'US');
+    }
+    notifyListeners();
+  }
+}

lib/main.dart

@@ -1,15 +1,18 @@
 //Flutter Packages are imported here
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
 
 //Pages are imported here
 import 'package:provider/provider.dart';
 import 'package:talawa/controllers/auth_controller.dart';
 import 'package:talawa/controllers/groups_controller.dart';
+import 'package:talawa/controllers/lang_controller.dart';
 import 'package:talawa/controllers/org_controller.dart';
 import 'package:talawa/controllers/signup_login_controller.dart';
 import 'package:talawa/controllers/url_controller.dart';
 import 'package:talawa/locator.dart';
+import 'package:talawa/services/app_localization.dart';
 import 'package:talawa/services/comment.dart';
 import 'package:talawa/controllers/news_feed_controller.dart';
 import 'package:talawa/services/navigation_service.dart';
@@ -28,6 +31,8 @@ LogHelper logHelper = LogHelper();
 Future<void> main() async {
   //ensuring weather the app is being initialized or not
   WidgetsFlutterBinding.ensureInitialized();
+  final AppLanguage appLanguage = AppLanguage();
+  await appLanguage.fetchLocale();
   setupLocator();
   await logHelper.init(); // To intialise FlutterLog
   SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp])
@@ -39,6 +44,7 @@ Future<void> main() async {
         ChangeNotifierProvider<OrgController>(create: (_) => OrgController()),
         ChangeNotifierProvider<AuthController>(create: (_) => AuthController()),
         ChangeNotifierProvider<Preferences>(create: (_) => Preferences()),
+        ChangeNotifierProvider.value(value: AppLanguage()),
         ChangeNotifierProvider<CommentHandler>(create: (_) => CommentHandler()),
         ChangeNotifierProvider<GroupController>(
             create: (_) => GroupController()),
@@ -56,45 +62,60 @@ Future<void> main() async {
 class MyApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
-    return GestureDetector(
-      onTap: () {
-        final FocusScopeNode currentFocus = FocusScope.of(context);
-        if (!currentFocus.hasPrimaryFocus &&
-            currentFocus.focusedChild != null) {
-          FocusManager.instance.primaryFocus.unfocus();
-        }
-      },
-      child: MaterialApp(
-        title: UIData.appName,
-        theme: ThemeData(
-          primaryColor: UIData.primaryColor,
-          fontFamily: UIData.quickFont,
-          primarySwatch: UIData.primaryColor as MaterialColor,
-        ),
-        debugShowCheckedModeBanner: false,
-        showPerformanceOverlay: false,
-        navigatorKey: locator<NavigationService>().navigatorKey,
-        onGenerateRoute: router.generateRoute,
-        home: FutureBuilder(
-          future: preferences.getUserId(),
-          initialData: "Initial Data",
-          builder: (BuildContext context, AsyncSnapshot snapshot) {
-            if (snapshot.data.toString() == "Initial Data") {
-              return Scaffold(
-                body: Container(
-                  child: const Center(
-                    child: CircularProgressIndicator(),
+    return Consumer<AppLanguage>(
+      builder: (context, appLang, _) => GestureDetector(
+        onTap: () {
+          final FocusScopeNode currentFocus = FocusScope.of(context);
+          if (!currentFocus.hasPrimaryFocus &&
+              currentFocus.focusedChild != null) {
+            FocusManager.instance.primaryFocus.unfocus();
+          }
+        },
+        child: MaterialApp(
+          locale: appLang.appLocal,
+          supportedLocales: [
+            const Locale('en', 'US'),
+            const Locale('es', 'ES'),
+            const Locale('fr', 'FR'),
+            const Locale('hi', 'IN'),
+            const Locale('zh-CN', 'CN'),
+          ],
+          localizationsDelegates: [
+            AppLocalizations.delegate,
+            GlobalMaterialLocalizations.delegate,
+            GlobalWidgetsLocalizations.delegate,
+          ],
+          title: UIData.appName,
+          theme: ThemeData(
+            primaryColor: UIData.primaryColor,
+            fontFamily: UIData.quickFont,
+            primarySwatch: UIData.primaryColor as MaterialColor,
+          ),
+          debugShowCheckedModeBanner: false,
+          showPerformanceOverlay: false,
+          navigatorKey: locator<NavigationService>().navigatorKey,
+          onGenerateRoute: router.generateRoute,
+          home: FutureBuilder(
+            future: preferences.getUserId(),
+            initialData: "Initial Data",
+            builder: (BuildContext context, AsyncSnapshot snapshot) {
+              if (snapshot.data.toString() == "Initial Data") {
+                return Scaffold(
+                  body: Container(
+                    child: const Center(
+                      child: CircularProgressIndicator(),
+                    ),
                   ),
-                ),
-              );
-            } else if (snapshot.hasError) {
-              throw FlutterError(
-                  'There is some error with "${snapshot.data}"\n');
-            } else if (snapshot.data != null) {
-              return const HomePage();
-            }
-            return UrlPage();
-          },
+                );
+              } else if (snapshot.hasError) {
+                throw FlutterError(
+                    'There is some error with "${snapshot.data}"\n');
+              } else if (snapshot.data != null) {
+                return const HomePage();
+              }
+              return UrlPage();
+            },
+          ),
         ),
       ),
     );

lib/services/app_localization.dart

@@ -0,0 +1,60 @@
+import 'dart:convert';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class AppLocalizations {
+  AppLocalizations(this.locale);
+  final Locale locale;
+
+  // Helper method to keep the code in the widgets concise
+  static AppLocalizations of(BuildContext context) {
+    return Localizations.of<AppLocalizations>(context, AppLocalizations);
+  }
+
+  // Static member to have a simple access to the delegate from the MaterialApp
+  static const LocalizationsDelegate<AppLocalizations> delegate =
+      _AppLocalizationsDelegate();
+
+  Map<String, String> _localizedStrings;
+
+  Future<bool> load() async {
+    // Load the language JSON file from the "lang" folder
+    final String jsonString =
+        await rootBundle.loadString('lang/${locale.languageCode}.json');
+    final Map<String, dynamic> jsonMap =
+        json.decode(jsonString) as Map<String, dynamic>;
+
+    _localizedStrings = jsonMap.map((key, value) {
+      return MapEntry(key, value.toString());
+    });
+
+    return true;
+  }
+
+  // This method will be called from every widget which needs a localized text
+  String translate(String key) {
+    return _localizedStrings[key];
+  }
+}
+
+class _AppLocalizationsDelegate
+    extends LocalizationsDelegate<AppLocalizations> {
+  const _AppLocalizationsDelegate();
+
+  @override
+  bool isSupported(Locale locale) {
+    // Include all of your supported language codes here
+    return ['en', 'es', 'fr', 'hi', 'zh-CN'].contains(locale.languageCode);
+  }
+
+  @override
+  Future<AppLocalizations> load(Locale locale) async {
+    // AppLocalizations class is where the JSON loading actually runs
+    final AppLocalizations localizations = AppLocalizations(locale);
+    await localizations.load();
+    return localizations;
+  }
+
+  @override
+  bool shouldReload(_AppLocalizationsDelegate old) => false;
+}

lib/views/pages/newsfeed/newsfeed.dart

@@ -7,6 +7,7 @@ import 'package:persistent_bottom_nav_bar/persistent-tab-view.dart';
 import 'package:provider/provider.dart';
 import 'package:talawa/controllers/news_feed_controller.dart';
 import 'package:talawa/model/posts.dart';
+import 'package:talawa/services/app_localization.dart';
 import 'package:talawa/utils/custom_toast.dart';
 import 'package:talawa/utils/ui_scaling.dart';
 import 'package:talawa/views/pages/newsfeed/add_post.dart';
@@ -25,6 +26,7 @@ class NewsFeed extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    //print(AppLocalizations.of(context).translate('hello-world'));
     return Scaffold(
       appBar: CustomAppBar(
         'NewsFeed',
@@ -118,12 +120,15 @@ class NewsFeed extends StatelessWidget {
                                                           .safeBlockHorizontal *
                                                       7.5,
                                                 ),
-                                                Text(
-                                                  post.title.toString(),
-                                                  softWrap: true,
-                                                  style: const TextStyle(
-                                                    fontWeight: FontWeight.bold,
-                                                    fontSize: 20.0,
+                                                // ignore: avoid_unnecessary_containers
+                                                Container(
+                                                  child: Text(
+                                                    post.title ?? '',
+                                                    style: const TextStyle(
+                                                      fontWeight:
+                                                          FontWeight.bold,
+                                                      fontSize: 20.0,
+                                                    ),
                                                   ),
                                                 ),
                                               ],

pubspec.yaml

@@ -22,6 +22,7 @@ dependencies:
   adhara_socket_io: ^0.4.1
   async: ^2.5.0
   carousel_slider: ^2.2.1
+  crypto: ^2.1.3
   cupertino_icons: ^0.1.2
   data_connection_checker: ^0.3.4
   datetime_picker_formfield: ^1.0.0
@@ -34,14 +35,14 @@ dependencies:
   flutter_logs: ^2.1.3
   flutter_masked_text: ^0.8.0
   flutter_password_strength: ^0.1.6
-  flutter_pw_validator: ^1.2.1
-  flutter_secure_storage: any
-  flutter_sticky_header: ^0.4.5
-  flutter_svg: ^0.20.0-nullsafety.3
-  fluttertoast: ^7.1.8
+  flutter_pw_validator:
+  flutter_secure_storage:
+  flutter_sticky_header:
+  flutter_svg:
+  fluttertoast:
   font_awesome_flutter:
   get_it: ^4.0.4
-  graphql_flutter: ^3.0.1
+  graphql_flutter: ^3.1.0
   grouped_buttons: ^1.0.4
   http: ^0.12.0+1
   image_picker: any
@@ -60,6 +61,8 @@ dependencies:
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
+dependency_overrides:
+  crypto: 3.0.1
 
 dev_dependencies:
   flutter_driver:
@@ -85,6 +88,7 @@ flutter:
   # To add assets to your application, add an assets section, like this:
   assets:
     - assets/images/
+    - lang/
 
   # assets:
   #  - images/a_dot_burr.jpeg