dependency_injection.md

Dependency Injection

Motivation

The included LocaleSettings should be enough for most use cases.

In big projects, developers tend to use a dependency injection solution.

You can make use of that to increase code quality.

Configuration

Please set the translation classes public:

# Config
locale_handling: false # remove unused t variable, LocaleSettings, etc.
translation_class_visibility: public

Usage

Call the build method in your enum to create a new translation instance of the desired locale.

If you have plurals, then you can also put your custom resolver into the build method.

Here is an example using the riverpod package.

final english = AppLocale.en.build();
final german = AppLocale.de.build();
final translationProvider = StateProvider<Translations>((ref) => german); // set it

// access the current instance
final t = ref.watch(translationProvider);
String a = t.welcome.title; // get translation
AppLocale locale = t.$meta.locale; // get locale

// initialize MaterialApp
MaterialApp(
  locale: ref.watch(translationProvider).$meta.locale.flutterLocale,
  supportedLocales: AppLocaleUtils.supportedLocales,
  localizationsDelegates: GlobalMaterialLocalizations.delegates, // from flutter_localizations package
  // ...
);

To make things easier, there are some utility functions in AppLocaleUtils.

// get locale as enum
AppLocale deviceLocale = AppLocaleUtils.findDeviceLocale();
AppLocale specificLocale = AppLocaleUtils.parse('en_US'); // handles '-' and '_'

// build instance
Translations translations = specificLocale.build();

// access instance
AppLocale locale = translations.$meta.locale;
String a = translations.welcome.title;