fast_i18n 1.8.1

Lightweight i18n solution. Use JSON files to create typesafe translations.

example/README.md

Example

Step 1: Add dependencies

dependencies:
  fast_i18n: ^1.8.1

dev_dependencies:
  build_runner: any

Step 2: Create JSON files

Create these files inside your lib directory. Preferably in one common package like lib/i18n.

strings.i18n.json (default, fallback)

{
  "hello": "Hello $name",
  "save": "Save",
  "login": {
    "success": "Logged in successfully",
    "fail": "Logged in failed"
  }
}

strings_de.i18n.json

{
  "hello": "Hallo $name",
  "save": "Speichern",
  "login": {
    "success": "Login erfolgreich",
    "fail": "Login fehlgeschlagen"
  }
}

config.i18n.json (optional but recommended)

{
  "baseLocale": "en"
}

Step 3: Generate the dart code

flutter pub run build_runner build

Step 4: Initialize

a) use device locale

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await LocaleSettings.useDeviceLocale();
  runApp(MyApp());
}

b) use specific locale

@override
void initState() {
  super.initState();
  String storedLocale = loadFromStorage(); // your logic here
  LocaleSettings.setLocale(storedLocale);
}

Step 4b: iOS-only

File: ios/Runner/Info.plist

<key>CFBundleLocalizations</key>
<array>
   <string>en</string>
   <string>de</string>
</array>

Step 5: Use your translations

// raw string
String translated = t.hello(name: 'Tom');

// inside component
Text(t.login.success)

// advanced
TranslationProvider(child: MyApp()); // wrap your app with the TranslationProvider
final t = Translations.of(context); // reacts on locale changes
String translateAdvanced = t.hello(name: 'Tom');

API

When the dart code has been generated, you will see some useful classes and functions

t - the translate variable for simple translations

Translations.of(context) - translations which reacts to locale changes

TranslationProvider - App wrapper, used for Translations.of(context)

LocaleSettings.useDeviceLocale() - use the locale of the device

LocaleSettings.setLocale('de') - change the locale

LocaleSettings.currentLocale - get the current locale

LocaleSettings.locales - get the supported locales

Configuration

All settings can be set in the config.i18n.json file. Place it anywhere inside your lib directory

{
  "baseLocale": "en",
  "maps": [
    "a",
    "b",
    "c.d"
  ]
}

Key	Type	Usage	Default
baseLocale	String	assign the default json file to a locale	''
maps	List<String>	entries which should be accessed via keys	[]

Additional features

Maps

Sometimes you need to access the translations via keys. Define the maps in your config.i18n.json. Keep in mind that all nice features like autocompletion are gone.

strings.i18n.json

{
  "welcome": "Welcome",
  "thisIsAMap": {
    "hello world": "hello"
  },
  "classicClass": {
    "hello": "hello",
    "aMapInClass": {
      "hi": "hi"
    }
  }
}

config.i18n.json

{
  "baseLocale": "en",
  "maps": [
    "thisIsAMap",
    "classicClass.aMapInClass"
  ]
}

Now you can access this via key:

String a = t.thisIsAMap['hello world'];
String b = t.classicClass.hello; // the "classical" way
String c = t.classicClass.aMapInClass['hi']; // nested

Lists

Lists are fully supported.

{
  "niceList": [
    "hello",
    "nice",
    [
      "nestedList"
    ],
    {
      "wow": "wow"
    },
    {
      "a map entry": "cool"
    }
  ]
}

String a = t.niceList[1];
String b = t.niceList[2][0];
String c = t.niceList[3].wow;
String d = t.niceList[4]['a map entry'];