Name: localization
Rating: 92
Author: avtansh-code

Localization Setup

The app uses Flutter's built-in flutter_localizations with ARB (Application Resource Bundle) files.

Supported locales (P0): English (en), Hindi (hi)

File Structure

code

lib/
├── l10n/
│   ├── app_en.arb          # English strings (source of truth)
│   ├── app_hi.arb          # Hindi translations
│   └── l10n.yaml           # Generation config
├── core/
│   └── l10n/
│       └── generated/      # Auto-generated (do not edit)
│           ├── app_localizations.dart
│           ├── app_localizations_en.dart
│           └── app_localizations_hi.dart

ARB File Format

English (source of truth)

json

{
  "@@locale": "en",
  "appTitle": "One By Two",
  "@appTitle": {
    "description": "App name shown in app bar"
  },
  "youOwe": "You owe {name}",
  "@youOwe": {
    "description": "Balance text when current user owes money",
    "placeholders": {
      "name": { "type": "String", "example": "Rahul" }
    }
  },
  "amountInRupees": "₹{amount}",
  "@amountInRupees": {
    "placeholders": {
      "amount": { "type": "String", "example": "150.50" }
    }
  },
  "expenseCount": "{count, plural, =0{No expenses} =1{1 expense} other{{count} expenses}}",
  "@expenseCount": {
    "description": "Number of expenses in a group",
    "placeholders": {
      "count": { "type": "int" }
    }
  },
  "memberCount": "{count, plural, =1{1 member} other{{count} members}}",
  "@memberCount": {
    "placeholders": {
      "count": { "type": "int" }
    }
  }
}

Hindi

json

{
  "@@locale": "hi",
  "appTitle": "वन बाय टू",
  "youOwe": "आप {name} को देते हैं",
  "amountInRupees": "₹{amount}",
  "expenseCount": "{count, plural, =0{कोई खर्च नहीं} =1{1 खर्च} other{{count} खर्चे}}",
  "memberCount": "{count, plural, =1{1 सदस्य} other{{count} सदस्य}}"
}

Usage in Code

dart

// Access localized strings
final l10n = AppLocalizations.of(context)!;
Text(l10n.appTitle);
Text(l10n.youOwe('Rahul'));
Text(l10n.expenseCount(5));
Text(l10n.amountInRupees('150.50'));

Adding New Strings

•Add to app_en.arb (English is always the source of truth)
•Add metadata with @key for description and placeholders
•Add to app_hi.arb with Hindi translation
•
Run code generation:
bash
```
flutter gen-l10n
```
•Use in code via AppLocalizations.of(context)!.newKey

Rules

•Never hardcode user-facing strings — always use ARB files
•English ARB is the source — Hindi follows; missing Hindi keys fall back to English
•Use ICU message format for plurals, selects, and gender
•Placeholders must be typed (String, int, double, DateTime)
•Amount formatting: Always format with ₹ symbol and 2 decimal places
•Date formatting: Use DateFormat from intl package, locale-aware
•Number formatting: Use NumberFormat from intl package for comma separators (Indian: 1,00,000)
•
Do NOT translate:
- •App name in marketing contexts ("One By Two")
- •Currency symbol (₹)
- •Technical identifiers

Indian Number Formatting

India uses a unique grouping: 1,00,000 (not 100,000).

dart

import 'package:intl/intl.dart';

String formatIndianAmount(int paise) {
  final rupees = paise / 100;
  final formatter = NumberFormat.currency(
    locale: 'en_IN',
    symbol: '₹',
    decimalDigits: 2,
  );
  return formatter.format(rupees);
}
// 1000000 paise → "₹10,000.00"
// 10000050 paise → "₹1,00,000.50"

l10n.yaml Configuration

yaml

arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
output-dir: lib/core/l10n/generated
synthetic-package: false
nullable-getter: false

Testing Localized Strings

dart

testWidgets('displays Hindi text when locale is hi', (tester) async {
  await tester.pumpWidget(
    MaterialApp(
      locale: const Locale('hi'),
      localizationsDelegates: AppLocalizations.localizationsDelegates,
      supportedLocales: AppLocalizations.supportedLocales,
      home: const HomeScreen(),
    ),
  );

  expect(find.text('वन बाय टू'), findsOneWidget);
});

Reference

•Requirements: docs/REQUIREMENTS.md (Section 7 — English + Hindi P0)
•Architecture: docs/architecture/01_ARCHITECTURE_OVERVIEW.md (i18n section)