How can I override Error Messages in the Firebase UI Auth package for multiple languages.

[stuartrapop]

Hello, I am a bit stuck on trying to override the error messages in the firebase_ui_auth package (which is overall excellent). I include the firebase_ui_localizations package.

I followed the doc (to the best of my abilities) and overrode some of the labels, but now all the non-overridden labels are in English.

I would be happy to use translations from my .arb files, but this does not seems possible.

In any case, any help welcome. Here is my code which allows overriding, but would force me to rewrite all the translations - a non tenable solution.

import 'package:firebase_ui_localizations/firebase_ui_localizations.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';

abstract class LabelOverridesBase extends FirebaseUILocalizationLabels {
  final FirebaseUILocalizationLabels defaultLabels;

  LabelOverridesBase(Locale locale)
      : defaultLabels =
            FirebaseUILocalizations(locale, DefaultLocalizations()).labels;

  static AppLocalizations? of(BuildContext context) {
    return Localizations.of<AppLocalizations>(context, AppLocalizations);
  }

  //  @override
  // dynamic noSuchMethod(Invocation invocation) {
  //   var memberName = invocation.memberName;
  //   var defaultMethod = defaultLabels.getClass().getMethod(memberName);
  //   if (defaultMethod != null) {
  //     return defaultMethod.invoke([]);
  //   }
  //   return super.noSuchMethod(invocation);
  // }

  @override
  String get signInText => defaultLabels.signInText;
  @override
  String get emailInputLabel => defaultLabels.emailInputLabel;
  @override
  String get arrayLabel => defaultLabels.arrayLabel;
  @override
  String get booleanLabel => defaultLabels.booleanLabel;
  @override
  String get cancelButtonLabel => defaultLabels.cancelButtonLabel;
  @override
  String get cancelLabel => defaultLabels.cancelLabel;
  @override
  String get checkEmailHintText => defaultLabels.checkEmailHintText;
  @override
  String get chooseACountry => defaultLabels.chooseACountry;
  @override
  String get confirmPasswordDoesNotMatchErrorText =>
      defaultLabels.confirmPasswordDoesNotMatchErrorText;
  @override
  String get confirmPasswordInputLabel =>
      defaultLabels.confirmPasswordInputLabel;
  @override
  String get confirmPasswordIsRequiredErrorText =>
      defaultLabels.confirmPasswordIsRequiredErrorText;
  @override
  String get confirmUnlinkButtonLabel => defaultLabels.confirmUnlinkButtonLabel;
  @override
  String get continueText => defaultLabels.continueText;
  @override
  String get countryCode => defaultLabels.countryCode;
  @override
  String get credentialAlreadyInUseErrorText =>
      defaultLabels.credentialAlreadyInUseErrorText;
  @override
  String get deleteAccount => defaultLabels.deleteAccount;
  @override
  String get differentMethodsSignInTitleText =>
      defaultLabels.differentMethodsSignInTitleText;
  @override
  String get disable => defaultLabels.disable;
  @override
  String get dismissButtonLabel => defaultLabels.dismissButtonLabel;
  @override
  String get doneButtonLabel => defaultLabels.doneButtonLabel;
  @override
  String get eastInitialLabel => defaultLabels.eastInitialLabel;
  @override
  String get emailIsNotVerifiedText => defaultLabels.emailIsNotVerifiedText;
  @override
  String get emailIsRequiredErrorText => defaultLabels.emailIsRequiredErrorText;
  @override
  String get emailLinkSignInButtonLabel =>
      defaultLabels.emailLinkSignInButtonLabel;
  @override
  String get emailTakenErrorText => defaultLabels.emailTakenErrorText;
  @override
  String get enable => defaultLabels.enable;
  @override
  String get enableMoreSignInMethods => defaultLabels.enableMoreSignInMethods;
  @override
  String get enterSMSCodeText => defaultLabels.enterSMSCodeText;
  @override
  String get findProviderForEmailTitleText =>
      defaultLabels.findProviderForEmailTitleText;
  @override
  String get forgotPasswordButtonLabel =>
      defaultLabels.forgotPasswordButtonLabel;
  @override
  String get forgotPasswordHintText => defaultLabels.forgotPasswordHintText;
  @override
  String get forgotPasswordViewTitle => defaultLabels.forgotPasswordViewTitle;
  @override
  String get geopointLabel => defaultLabels.geopointLabel;
  @override
  String get goBackButtonLabel => defaultLabels.goBackButtonLabel;
  @override
  String get invalidCountryCode => defaultLabels.invalidCountryCode;
  @override
  String get invalidVerificationCodeErrorText =>
      defaultLabels.invalidVerificationCodeErrorText;
  @override
  String get isNotAValidEmailErrorText =>
      defaultLabels.isNotAValidEmailErrorText;
  @override
  String get latitudeLabel => defaultLabels.latitudeLabel;
  @override
  String get linkEmailButtonText => defaultLabels.linkEmailButtonText;
  @override
  String get longitudeLabel => defaultLabels.longitudeLabel;
  @override
  String get mapLabel => defaultLabels.mapLabel;
  @override
  String get mfaTitle => defaultLabels.mfaTitle;
  @override
  String get name => defaultLabels.name;
  @override
  String get northInitialLabel => defaultLabels.northInitialLabel;
  @override
  String get nullLabel => defaultLabels.nullLabel;
  @override
  String get numberLabel => defaultLabels.numberLabel;
  @override
  String get off => defaultLabels.off;
  @override
  String get okButtonLabel => defaultLabels.okButtonLabel;
  @override
  String get on => defaultLabels.on;
  @override
  String get passwordInputLabel => defaultLabels.passwordInputLabel;
  @override
  String get passwordIsRequiredErrorText =>
      defaultLabels.passwordIsRequiredErrorText;
  @override
  String get passwordResetEmailSentText =>
      defaultLabels.passwordResetEmailSentText;
  @override
  String get phoneInputLabel => defaultLabels.phoneInputLabel;
  @override
  String get phoneNumberInvalidErrorText =>
      defaultLabels.phoneNumberInvalidErrorText;
  @override
  String get phoneNumberIsRequiredErrorText =>
      defaultLabels.phoneNumberIsRequiredErrorText;
  @override
  String get phoneVerificationViewTitleText =>
      defaultLabels.phoneVerificationViewTitleText;
  @override
  String get profile => defaultLabels.profile;
  @override
  String get provideEmail => defaultLabels.provideEmail;
  @override
  String get referenceLabel => defaultLabels.referenceLabel;
  @override
  String get registerActionText => defaultLabels.registerActionText;
  @override
  String get registerHintText => defaultLabels.registerHintText;
  @override
  String get registerText => defaultLabels.registerText;
  @override
  String get resendVerificationEmailButtonLabel =>
      defaultLabels.resendVerificationEmailButtonLabel;
  @override
  String get resetPasswordButtonLabel => defaultLabels.resetPasswordButtonLabel;
  @override
  String get sendLinkButtonLabel => defaultLabels.sendLinkButtonLabel;
  @override
  String get signInActionText => defaultLabels.signInActionText;
  @override
  String get signInHintText => defaultLabels.signInHintText;
  @override
  String get signInMethods => defaultLabels.signInMethods;
  @override
  String get signInWithAppleButtonText =>
      defaultLabels.signInWithAppleButtonText;
  @override
  String get signInWithEmailLinkSentText =>
      defaultLabels.signInWithEmailLinkSentText;
  @override
  String get signInWithEmailLinkViewTitleText =>
      defaultLabels.signInWithEmailLinkViewTitleText;
  @override
  String get signInWithFacebookButtonText =>
      defaultLabels.signInWithFacebookButtonText;
  @override
  String get signInWithGoogleButtonText =>
      defaultLabels.signInWithGoogleButtonText;
  @override
  String get signInWithPhoneButtonText =>
      defaultLabels.signInWithPhoneButtonText;
  @override
  String get signInWithTwitterButtonText =>
      defaultLabels.signInWithTwitterButtonText;
  @override
  String get signOutButtonText => defaultLabels.signOutButtonText;
  @override
  String get smsAutoresolutionFailedError =>
      defaultLabels.smsAutoresolutionFailedError;
  @override
  String get southInitialLabel => defaultLabels.southInitialLabel;
  @override
  String get stringLabel => defaultLabels.stringLabel;
  @override
  String get timestampLabel => defaultLabels.timestampLabel;
  @override
  String get typeLabel => defaultLabels.typeLabel;
  @override
  String get ulinkProviderAlertTitle => defaultLabels.ulinkProviderAlertTitle;
  @override
  String get unknownError => defaultLabels.unknownError;
  @override
  String get unlinkProviderAlertMessage =>
      defaultLabels.unlinkProviderAlertMessage;
  @override
  String get updateLabel => defaultLabels.updateLabel;
  @override
  String get uploadButtonText => defaultLabels.uploadButtonText;
  @override
  String get userNotFoundErrorText => defaultLabels.userNotFoundErrorText;
  @override
  String get valueLabel => defaultLabels.valueLabel;
  @override
  String get verificationEmailSentTextShort =>
      defaultLabels.verificationEmailSentTextShort;
  @override
  String get verificationFailedText => defaultLabels.verificationFailedText;
  @override
  String get verifyCodeButtonText => defaultLabels.verifyCodeButtonText;
  @override
  String get verifyEmailTitle => defaultLabels.verifyEmailTitle;
  @override
  String get verifyItsYouText => defaultLabels.verifyItsYouText;
  @override
  String get verifyPhoneNumberButtonText =>
      defaultLabels.verifyPhoneNumberButtonText;
  @override
  String get verifyingSMSCodeText => defaultLabels.verifyingSMSCodeText;
  @override
  String get waitingForEmailVerificationText =>
      defaultLabels.waitingForEmailVerificationText;
  @override
  String get weakPasswordErrorText => defaultLabels.weakPasswordErrorText;
  @override
  String get westInitialLabel => defaultLabels.westInitialLabel;
  @override
  String get wrongOrNoPasswordErrorText =>
      defaultLabels.wrongOrNoPasswordErrorText;
  @override
  String get confirmDeleteAccountAlertMessage =>
      defaultLabels.confirmDeleteAccountAlertMessage;
  @override
  String get confirmDeleteAccountButtonLabel =>
      defaultLabels.confirmDeleteAccountButtonLabel;
  @override
  String get confirmDeleteAccountAlertTitle =>
      defaultLabels.confirmDeleteAccountAlertTitle;
}

class LabelOverridesEN extends LabelOverridesBase {
  LabelOverridesEN(Locale locale) : super(locale);
  @override
  String get verificationEmailSentText =>
      'A custom verification email has been sent...';
  @override
  String get accessDisabledErrorText =>
      'Custom access to this account has been temporarily disabled...';
}

class LabelOverridesFR extends LabelOverridesBase {
  LabelOverridesFR(Locale locale) : super(locale);
  @override
  String get verificationEmailSentText => 'French translation...';
  @override
  String get accessDisabledErrorText => 'French translation...';
}

class LabelOverridesDelegate
    extends LocalizationsDelegate<FirebaseUILocalizations> {
  const LabelOverridesDelegate();
  @override
  bool isSupported(Locale locale) =>
      ['de', 'en', 'es', 'fr'].contains(locale.languageCode);

  @override
  Future<FirebaseUILocalizations> load(Locale locale) {
    LabelOverridesBase labels;
    switch (locale.languageCode) {
      case 'en':
        labels = LabelOverridesEN(locale);
        break;
      case 'fr':
        labels = LabelOverridesFR(locale);
        break;
      // ... cases for other languages ...
      default:
        labels = LabelOverridesEN(locale); // Default case
        break;
    }

    return SynchronousFuture<FirebaseUILocalizations>(
        FirebaseUILocalizations(locale, labels));
  }

  @override
  bool shouldReload(LocalizationsDelegate<FirebaseUILocalizations> old) =>
      false;
}