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'];