Custom localization mismatch with the general app localizations

[FaisalMohammadi]

Is there an existing issue for this?

• I have searched the existing issues

Package/Plugin version

11.0.0

Platforms

• Android
• iOS
• Linux
• MacOS
• Web
• Windows

Flutter doctor

Flutter doctor

[✓] Flutter (Channel stable, 3.24.1, on macOS 14.5 23F79
    darwin-arm64, locale de-DE)
    • Flutter version 3.24.1 on channel stable at
      /Users/faisalmohammadi/fvm/versions/stable
    • Upstream repository
      https://github.com/flutter/flutter.git
    • Framework revision 5874a72aa4 (4 months ago),
      2024-08-20 16:46:00 -0500
    • Engine revision c9b9d5780d
    • Dart version 3.5.1
    • DevTools version 2.37.2

[✓] Android toolchain - develop for Android devices
    (Android SDK version 34.0.0)
    • Android SDK at
      /Users/faisalmohammadi/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • ANDROID_HOME =
      /Users/faisalmohammadi/Library/Android/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

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      Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2022.2)
    • Android Studio at /Applications/Android
      Studio.app/Contents
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      🔨
      https://plugins.jetbrains.com/plugin/9212-flutter
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      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build
      17.0.6+0-17.0.6b802.4-9586694)

[✓] VS Code (version 1.95.3)
    • VS Code at /Applications/Visual Studio
      Code.app/Contents
    • Flutter extension version 3.102.0

[✓] Connected device (4 available)
    • iPhone 13 mini (mobile)         •
      7E675357-3D1E-4428-8BB7-5720CB02D06F • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-16-4
      (simulator)
    • macOS (desktop)                 • macos
      • darwin-arm64   • macOS 14.5 23F79 darwin-arm64
    • Mac Designed for iPad (desktop) •
      mac-designed-for-ipad                • darwin
      • macOS 14.5 23F79 darwin-arm64
    • Chrome (web)                    • chrome
      • web-javascript • Google Chrome 131.0.6778.109
    ! Error: Browsing on the local area network for
      Michaels iPhone. Ensure the device is unlocked and
      attached with a cable or associated with the same
      local area network as this Mac.
      The device must be opted into Developer Mode to
      connect wirelessly. (code -27)
    ! Error: Browsing on the local area network for
      Faisal M . Ensure the device is unlocked and
      attached with a cable or associated with the same
      local area network as this Mac.
      The device must be opted into Developer Mode to
      connect wirelessly. (code -27)

[✓] Network resources
    • All expected network resources are available.

• No issues found!

Minimal code example

Code sample

                  localizationsDelegates: const [
                    OverrideFormBuilderLocalizationsDe.delegate,
                    OverrideFormBuilderLocalizationsEn.delegate,
                    S.delegate,
                    FormBuilderLocalizations.delegate,
                    GlobalMaterialLocalizations.delegate,
                    GlobalWidgetsLocalizations.delegate,
                    GlobalCupertinoLocalizations.delegate,
                  ],

                  supportedLocales: [
                    Locale('de'),
                    Locale('en'),
                  ],

Current Behavior

currently not possible to use both localizations in paralell. Either the general app localization not working or the form_builder_validators custom localization not working.
i created the two classes OverrideFormBuilderLocalizationsDe and OverrideFormBuilderLocalizationsEn and added it inside main.dart as its shown in the minimal code section above.

the main problem relies in the supportedLocales section

like this working the form_builder_validators localization but not the general app localization

 supportedLocales: [
                    Locale('de'),
                    Locale('en'),
                  ],

**like this the general app localization working but not form_builder_validators localization **

 supportedLocales: [
                    Locale('en', 'US'),
                    Locale('de', 'DE'),
                  ],

Expected Behavior

using like this i expect to work both my general app localization and also my custom localization for form_builder_validators

                  localizationsDelegates: const [
                    OverrideFormBuilderLocalizationsDe.delegate,
                    OverrideFormBuilderLocalizationsEn.delegate,
                    S.delegate,
                    FormBuilderLocalizations.delegate,
                    GlobalMaterialLocalizations.delegate,
                    GlobalWidgetsLocalizations.delegate,
                    GlobalCupertinoLocalizations.delegate,
                  ],

                  supportedLocales: [
                    Locale('en', 'US'),
                    Locale('de', 'DE'),
                  ],

Steps To Reproduce

1. add form_builder_validators package.
2. set up general app localitaion with intl
3. setup the custom localization for the form_builder_validators package by following the docs inside
4. override some fileds of form_builder_validators
5. add all deligates in main.dart as shown above in the Minimal code example
6. add supportedLocales like this

supportedLocales: [
                    Locale('de'),
                    Locale('en'),
                  ], 
                  ```
7. run the app and check. The `form_builder_validators` works and not the general app localization
8. change the supportedLocales to this 
```dart 
supportedLocales: [
                    Locale('en', 'US'),
                    Locale('de', 'DE'),
                  ], 
                  ```
9: run the app and check. The general app localization works but not `form_builder_validators` 


### Aditional information

_No response_

[quyenvsp]

we should use intl_utils instead of gen_l10n, then use https://pub.dev/packages/multiple_localization
for override package localization