# Regenerating the i18n files The files in this directory are used to generate `stock_strings.dart`, which is used by the stocks application to look up localized message strings. The stocks app uses the [Dart `intl` package](https://github.com/dart-lang/intl). Rebuilding everything requires two steps. 1. Create or update the English and Spanish localizations, `stocks_en_US.arb` and `stocks_es_ES.arb`. See the [ARB specification](https://github.com/google/app-resource-bundle/wiki/ApplicationResourceBundleSpecification) for more info. 2. With `examples/stocks` as the current directory, generate a `messages_<locale>.dart` for each `stocks_<locale>.arb` file, `messages_all.dart`, and `stock_strings.dart` with the following command: ```dart dart ${FLUTTER_PATH}/dev/tools/localization/gen_l10n.dart --arb-dir=lib/i18n \ --template-arb-file=stocks_en_US.arb --output-localization-file=stock_strings.dart \ --output-class=StockStrings ``` The `StockStrings` class uses the generated `initializeMessages()`function (`messages_all.dart`) to load the localized messages and `Intl.message()` to look them up. The generated class's API documentation explains how to add the new localizations delegate and supported locales to the Flutter application.