Merge pull request #76 from defint/namespace-file-loader

Namespace file loader

README.md

@@ -1,6 +1,10 @@
 # flutter_i18n
 I18n made easy, for Flutter!
 
+<!-- Badges -->
+[![Pub Package](https://img.shields.io/pub/v/flutter_i18n.svg)](https://pub.dev/packages/flutter_i18n)
+[![GitHub Actions](https://github.com/ilteoood/flutter_i18n/workflows/Publish%20plugin/badge.svg)](https://github.com/ilteoood/flutter_i18n/actions)
+
 ------------------------------------------------
 
 
@@ -19,10 +23,11 @@ You can easy override loader and create your own.
 Available loaders:
 
 | Class name | Purpose |  
-| - | - |
+| --- | --- |
 | `FileTranslationLoader` |  Loads translation files from JSON or YAML format | 
 | `NetworkFileTranslationLoader` | Loads translations from the remote resource | 
-| `E2EFileTranslation loader` | Special loader for solving isolates problem with flutter drive  |
+| `NamespaceFileTranslationLoader` | Loads translations from separate files |
+| `E2EFileTranslationLoader` | Special loader for solving isolates problem with flutter drive |
 
 ### `FileTranslationLoader` configuration
 
@@ -80,7 +85,7 @@ If there isn't any translation available for the required key, the same key is r
 
 ### `NetworkFileTranslationLoader` configuration
 
-Behaviour of this loader very similar as `FileTranslationLoader`. The main different that we load translations from `NetworkAssetBundle` instead of `CachingAssetBundle`.
+Behaviour of this loader very similar as `FileTranslationLoader`. The main difference that we load translations from `NetworkAssetBundle` instead of `CachingAssetBundle`.
 
 Below you can find the name and description of the accepted parameters.
 
@@ -106,6 +111,51 @@ localizationsDelegates: [
 ],
 ```
 
+### `NamespaceFileTranslationLoader` configuration
+
+Behaviour of this loader very similar as `FileTranslationLoader`. The main difference that we load translations from separate files per each language.
+
+For example `FileTranslationLoader` format:
+
+> /assets/flutter_i18n/en.json
+>
+> /assets/flutter_i18n/it.json
+
+`NamespaceFileTranslationLoader` format:
+
+> /assets/flutter_i18n/en/home_screen.json
+>
+> /assets/flutter_i18n/en/about_screen.json
+>
+> /assets/flutter_i18n/it/home_screen.json
+>
+> /assets/flutter_i18n/it/about_screen.json
+
+Example configuration:
+
+```dart
+localizationsDelegates: [
+        FlutterI18nDelegate(translationLoader: 
+          NamespaceFileTranslationLoader(namespaces: ["home_screen", "about_screen"]),
+        GlobalMaterialLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate
+],
+```
+
+Below you can find the name and description of the accepted parameters.
+
+The ***namespaces*** provide a list of filenames for the specific language directory.
+
+The ***useCountryCode*** parameter depends on the *json* configuration:
+- if you used the pattern {languageCode}_{countryCode}, ***useCountryCode*** must be **true**
+- if you used the pattern {languageCode}, ***useCountryCode*** must be **false**
+
+The ***fallbackDir*** provide a default language directory, used when the translation for the current running system is not provided.
+
+The ***basePath*** parameter is optionally used to set the base path for translations. If this option is not set, the default path will be `assets/flutter_i18n`. This path must be the same path as the one defined in your ***pubspec.yaml***.
+
+The ***forcedLocale*** parameter is optionally used to force a locale instead finding the system one.
+
 ### `E2EFileTranslationLoader` configuration
 
 The same as `FileTranslationLoader` configuration. This loader can be used for solving problem with flutter drive testing.

example/assets/i18n_namespace/en/common.json

@@ -0,0 +1,3 @@
+{
+  "title": "Namespace example"
+}

example/assets/i18n_namespace/en/home.yaml

@@ -0,0 +1,2 @@
+label:
+  main: "Label from another namespace"

example/assets/i18n_namespace/ua/common.json

@@ -0,0 +1,3 @@
+{
+  "title": "Приклад простору імен"
+}

example/assets/i18n_namespace/ua/home.json

@@ -0,0 +1,5 @@
+{
+  "label": {
+    "main": "Напис з іншого простору імен"
+  }
+}

example/lib/main.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 
 import 'basic_example.dart' as basicExample;
+import 'namespace_example.dart' as namespaceExample;
 import 'network_example.dart' as networkExample;
 
 Future main() async {
@@ -38,6 +39,12 @@ class MyApp extends StatelessWidget {
                     },
                     child: Text("Run `network` example"),
                   ),
+                  RaisedButton(
+                    onPressed: () {
+                      namespaceExample.main();
+                    },
+                    child: Text("Run `namespace` example"),
+                  ),
                 ],
               ));
             })));

example/lib/namespace_example.dart

@@ -0,0 +1,79 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_i18n/flutter_i18n.dart';
+import 'package:flutter_i18n/widgets/I18nText.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+
+Future main() async {
+  final FlutterI18nDelegate flutterI18nDelegate = FlutterI18nDelegate(
+    translationLoader: NamespaceFileTranslationLoader(
+        namespaces: ["common", "home"],
+        useCountryCode: false,
+        fallbackDir: 'en',
+        basePath: 'assets/i18n_namespace',
+        forcedLocale: Locale('it')),
+  );
+  WidgetsFlutterBinding.ensureInitialized();
+  runApp(MyApp(flutterI18nDelegate));
+}
+
+class MyApp extends StatelessWidget {
+  final FlutterI18nDelegate flutterI18nDelegate;
+
+  MyApp(this.flutterI18nDelegate);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      theme: ThemeData(
+        primarySwatch: Colors.deepPurple,
+      ),
+      home: MyHomePage(),
+      localizationsDelegates: [
+        flutterI18nDelegate,
+        GlobalMaterialLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate
+      ],
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  @override
+  MyHomeState createState() => MyHomeState();
+}
+
+class MyHomeState extends State<MyHomePage> {
+  changeLanguage() async {
+    final currentLang = FlutterI18n.currentLocale(context);
+    final nextLang =
+        currentLang.languageCode == 'ua' ? Locale('en') : Locale('ua');
+    await FlutterI18n.refresh(context, nextLang);
+    setState(() {});
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar:
+          AppBar(title: Text(FlutterI18n.translate(context, "common.title"))),
+      body: Builder(builder: (BuildContext context) {
+        return Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: <Widget>[
+              I18nText("home.label.main", Text("")),
+              RaisedButton(
+                  onPressed: () async {
+                    await changeLanguage();
+                  },
+                  child: Text("Change language"))
+            ],
+          ),
+        );
+      }),
+    );
+  }
+}

example/pubspec.yaml

@@ -15,6 +15,8 @@ flutter:
   uses-material-design: true
   assets:
     - assets/i18n/
+    - assets/i18n_namespace/en/
+    - assets/i18n_namespace/ua/
 
 environment:
   sdk: '>=1.19.0 <3.0.0'

lib/flutter_i18n.dart

@@ -9,6 +9,7 @@ import 'package:flutter_i18n/utils/simple_translator.dart';
 export 'flutter_i18n_delegate.dart';
 export 'loaders/e2e_file_translation_loader.dart';
 export 'loaders/file_translation_loader.dart';
+export 'loaders/namespace_file_translation_loader.dart';
 export 'loaders/network_file_translation_loader.dart';
 export 'loaders/translation_loader.dart';
 export 'widgets/I18nPlural.dart';

lib/loaders/file_translation_loader.dart

@@ -23,7 +23,7 @@ class FileTranslationLoader extends TranslationLoader {
   @override
   set locale(Locale locale) => _locale = locale;
 
-  Map<dynamic, dynamic> _decodedMap;
+  Map<dynamic, dynamic> _decodedMap = Map();
 
   FileTranslationLoader(
       {this.fallbackFile = "en",
@@ -50,41 +50,46 @@ class FileTranslationLoader extends TranslationLoader {
   Future _loadCurrentTranslation() async {
     this.locale = locale ?? await findCurrentLocale();
     MessagePrinter.info("The current locale is ${this.locale}");
-    await _loadFile(_composeFileName());
+    _decodedMap = await loadFile(composeFileName());
   }
 
   Future _loadFallback() async {
     try {
-      await _loadFile(fallbackFile);
+      _decodedMap = await loadFile(fallbackFile);
     } catch (e) {
       MessagePrinter.debug('Error loading translation fallback $e');
-      _decodedMap = Map();
     }
   }
 
-  Future<void> _loadFile(final String fileName) async {
+  Future<Map> loadFile(final String fileName) async {
+    Map<dynamic, dynamic> result;
+
     try {
-      await _decodeFile(fileName, 'json', json.decode);
+      result = await _decodeFile(fileName, 'json', json.decode);
       MessagePrinter.info("JSON file loaded for $fileName");
     } on Error catch (_) {
       MessagePrinter.debug(
           "Unable to load JSON file for $fileName, I'm trying with YAML");
-      await _decodeFile(fileName, 'yaml', loadYaml);
+      result = await _decodeFile(fileName, 'yaml', loadYaml);
       MessagePrinter.info("YAML file loaded for $fileName");
     }
+
+    return result;
   }
 
-  Future<void> _decodeFile(final String fileName, final String extension,
+  Future<Map> _decodeFile(final String fileName, final String extension,
       final Function decodeFunction) async {
-    _decodedMap = await loadString(fileName, extension)
+    return loadString(fileName, extension)
         .then((fileContent) => decodeFunction(fileContent));
   }
 
-  String _composeFileName() {
-    return "${locale.languageCode}${_composeCountryCode()}";
+  @protected
+  String composeFileName() {
+    return "${locale.languageCode}${composeCountryCode()}";
   }
 
-  String _composeCountryCode() {
+  @protected
+  String composeCountryCode() {
     String countryCode = "";
     if (useCountryCode && locale.countryCode != null) {
       countryCode = "_${locale.countryCode}";

lib/loaders/namespace_file_translation_loader.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/services.dart';
+import 'package:flutter/services.dart' show rootBundle;
+import 'package:flutter/widgets.dart';
+import 'package:flutter_i18n/loaders/file_translation_loader.dart';
+import 'package:flutter_i18n/utils/message_printer.dart';
+
+class NamespaceFileTranslationLoader extends FileTranslationLoader {
+  final String fallbackDir;
+  final String basePath;
+  final bool useCountryCode;
+  final Locale forcedLocale;
+  final List<String> namespaces;
+  AssetBundle assetBundle;
+
+  Map<dynamic, dynamic> _decodedMap = {};
+
+  NamespaceFileTranslationLoader(
+      {@required this.namespaces,
+      this.fallbackDir = "en",
+      this.basePath = "assets/flutter_i18n",
+      this.useCountryCode = false,
+      this.forcedLocale}) {
+    assert(namespaces != null);
+    assert(namespaces.length > 0);
+
+    assetBundle = rootBundle;
+  }
+
+  Future<Map> load() async {
+    this.locale = locale ?? await findCurrentLocale();
+    MessagePrinter.info("The current locale is ${this.locale}");
+
+    await Future.wait(
+        namespaces.map((namespace) => _loadTranslation(namespace)));
+
+    return _decodedMap;
+  }
+
+  Future<void> _loadTranslation(String namespace) async {
+    _decodedMap[namespace] = Map();
+
+    try {
+      _decodedMap[namespace] =
+          await loadFile("${composeFileName()}/$namespace");
+    } catch (e) {
+      MessagePrinter.debug('Error loading translation $e');
+      await _loadTranslationFallback(namespace);
+    }
+  }
+
+  Future<void> _loadTranslationFallback(String namespace) async {
+    try {
+      _decodedMap[namespace] = await loadFile("$fallbackDir/$namespace");
+    } catch (e) {
+      MessagePrinter.debug('Error loading translation fallback $e');
+    }
+  }
+}