Flutter Localization Setup

Goal

Configures and implements internationalization (i18n) and localization (l10n) in a Flutter application. This skill manages dependency injection (flutter_localizations, intl), code generation configuration (l10n.yaml), root widget setup (MaterialApp, CupertinoApp, or WidgetsApp), .arb translation file management, and platform-specific configurations (iOS Xcode project updates). It ensures proper locale resolution and prevents common assertion errors related to missing localization delegates in specific widgets like TextField and CupertinoTabBar.

Decision Logic

1. Determine App Root: Identify if the application uses MaterialApp, CupertinoApp, or WidgetsApp to inject the correct global delegates.
2. Identify Target Platforms: If iOS is a target platform, Xcode project files (Info.plist / project.pbxproj) must be updated to expose supported locales to the App Store.
3. Analyze Widget Tree: Check for isolated TextField or CupertinoTabBar widgets that might exist outside the root app's localization scope. If found, wrap them in explicit Localizations widgets.
4. Determine Locale Complexity: If supporting languages with multiple scripts/regions (e.g., Chinese zh_Hans_CN), use Locale.fromSubtags instead of the default Locale constructor.

Instructions