fast_i18n 1.5.0

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

example/README.md

Example

Step 1: Add dependencies

dependencies:
  fast_i18n: ^1.4.0

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

{
  "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 packages pub run build_runner build

Step 4: Initialize

@override
void initState() {
  super.initState();

  // a: use device locale
  LocaleSettings.useDeviceLocale().whenComplete(() {
    setState((){});
  });

  // b: use specific locale
  LocaleSettings.setLocale('de');

  // c: use default locale (default json locale)
  // *do nothing*
}

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)

API

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

t - the most important translate variable

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

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'];