Why is this null error showing up in my localization structure when loading maps that should initialize?

Question

Can someone point out why I'm getting a null error where loading text within my localizations structure.

Error commented below at authSighInText.

The only thing I can think of is that _localizedValues is not initialized yet upon app launch. Should I be moving this earlier into main or something?

My language structure:

class AppLocalizationsDelegate extends LocalizationsDelegate<TextContent> {
  const AppLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) => TextContent.languages().contains(locale.languageCode);

  @override
  Future<TextContent> load(Locale locale) {
    return SynchronousFuture<TextContent>(TextContent(locale));
  }

  @override
  bool shouldReload(AppLocalizationsDelegate old) => false;
}

class TextContent {
  TextContent(this.locale);
  final Locale locale;

  static TextContent of(BuildContext context) {
    return Localizations.of<TextContent>(context, TextContent)!;
  }

  // Add language list conglomeration from TextUtility here
  static final _localizedValues = <String, Map<String, String>>{
    'en': TextUtility.englishTexts(),
  };

  static List<String> languages() => _localizedValues.keys.toList();

  /* **********************************************************************************************
  Infrastructure Authentication Texts
  ************************************************************************************************/

  String get authSignInText {
    return _localizedValues[locale.languageCode]!['signIn']!;    // NULL ERROR HERE...???
  }

  String get authFormEmailText {
    return _localizedValues[locale.languageCode]!['email']!;
  }

  String get authFormPasswordText {
    return _localizedValues[locale.languageCode]!['password']!;
  }

...
}

Maps:

abstract class TextUtility {
  ///
  /// All english text maps to be manually hardcoded into this list.
  static List<Map<String, String>> englishTextLists = [
    InfrastructureAuthenticationText.authenticationText,
    InfrastructureFormValidationErrorText.invalidEmailText,
    InfrastructureDialogMessagesText.dialogMessagesText,
  ];

  ///
  /// English texts.
  ///
  /// Method conglomerates all texts from above english files into one map. This method is called
  /// within LanguageLocalizations TextContent.
  ///
  /// Returns:
  ///   [Map<String, String>]
  static Map<String, String> englishTexts() {
    Map<String, String> allEnglishTexts = {};
    for (int i = 0; i < englishTextLists.length; i++) {
      allEnglishTexts.addAll(englishTextLists[i]);
    }
    return allEnglishTexts;
  }
}

Language texts:

abstract class InfrastructureAuthenticationText {
  static const Map<String, String> authenticationText = {
    // Account actions
    'sign_in': 'Sign In',
    'sign_out': 'Sign Out',
    'sign_up': 'Sign Up',
    'sign_up punctuated': 'Sign Up.',

    ...
  };
}

Where text call is made:

Text(
            TextContent.of(context).authSignInText,
            style: ThemeEndpoints.primaryHeader(),
          ),

Answer 1

You need to do that :

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await EasyLocalization.ensureInitialized();
  SystemChrome.setPreferredOrientations(
      [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown]).then((_) {
    runApp(EasyLocalization(
        supportedLocales: [Locale('en', 'US'), Locale('bn', 'BN')],
        path: 'lib/asset/translations',
        fallbackLocale: Locale('en', 'US'),
        saveLocale: true,
        child: MyApp()));
  });
}