Localization

Basic Strings

{
  "@@locale": "en",
  "appTitle": "One By Two",
  "@appTitle": { "description": "App name displayed in app bar" }
}

Strings with Placeholders

{
  "youOwe": "You owe {amount}",
  "@youOwe": {
    "description": "Text showing how much user owes",
    "placeholders": {
      "amount": { "type": "String", "example": "₹2,450" }
    }
  }
}

Pluralization (ICU Format)

{
  "expenseCount": "{count, plural, =0{No expenses} =1{1 expense} other{{count} expenses}}",
  "@expenseCount": {
    "description": "Number of expenses with pluralization",
    "placeholders": {
      "count": { "type": "int" }
    }
  }
}

Select (Enum-like)

{
  "splitType": "{type, select, equal{Split equally} exact{Exact amounts} percentage{By percentage} shares{By shares} itemized{Itemized} other{Unknown}}",
  "@splitType": {
    "description": "Split type label",
    "placeholders": {
      "type": { "type": "String" }
    }
  }
}

Key Naming Conventions

• camelCase for all keys: groupSettingsTitle, addExpenseButton
• Prefix by screen/feature when keys are screen-specific: groupDetailTitle, groupDetailEmptyState
• Generic keys for reusable strings: cancel, save, delete, retry

Indian Number Formatting

Pattern

Indian numbering uses lakhs and crores, not millions:

Formatting in Code

// Use the project's AmountFormatter — never format manually
import 'package:one_by_two/core/utils/amount_formatter.dart';

// Full format: "₹1,00,000"
final display = AmountFormatter.formatAmount(10000000); // 10000000 paise = ₹1,00,000

// Compact: "₹1L", "₹1Cr"
final compact = AmountFormatter.formatCompact(10000000);

Rules

• All monetary values stored as int paise (1 rupee = 100 paise).
• Format only at the display layer — never store formatted strings.
• Amount placeholders in ARB files are always String type (pre-formatted with ₹ symbol).
• Negative amounts display as "−₹500" (minus sign, not hyphen).

Usage in Code

Accessing Translations

import 'package:flutter_gen/gen_l10n/app_localizations.dart';

// Direct access in widgets
Text(AppLocalizations.of(context).youOwe(formattedAmount))

Context Extension (Preferred)

extension LocalizationExtension on BuildContext {
  AppLocalizations get l10n => AppLocalizations.of(this);
}

// Shorter usage
Text(context.l10n.youOwe(formattedAmount))
Text(context.l10n.expenseCount(expenses.length))

In Non-Widget Code

Pass AppLocalizations explicitly when needed outside the widget tree:

String buildNotificationBody(AppLocalizations l10n, int amountPaise) {
  final formatted = AmountFormatter.formatAmount(amountPaise);
  return l10n.youOwe(formatted);
}

After Editing ARB Files

# Generate localization code
flutter gen-l10n

# Verify no issues
flutter analyze

Always run these two commands after any ARB file change. CI will fail if generated code is out of sync.

Translation Checklist

• All keys present in both app_en.arb and app_hi.arb
• Plurals use ICU format (=0, =1, other)
• Placeholders have type annotations
• Amount placeholders are String type (pre-formatted with ₹)
• Error messages are user-friendly, not technical
• Hindi translations reviewed for natural phrasing (not literal word-for-word)
• Run flutter gen-l10n after every edit
• Run flutter analyze to catch missing keys or type errors

Common Patterns

Error Messages

{
  "errorGeneric": "Something went wrong. Please try again.",
  "errorNoInternet": "No internet connection. Your changes will sync when you're back online.",
  "errorExpenseNotFound": "This expense was deleted or doesn't exist anymore."
}

Confirmation Dialogs

{
  "deleteExpenseTitle": "Delete expense?",
  "deleteExpenseBody": "This will remove the expense for all members. This action cannot be undone.",
  "deleteConfirm": "Delete",
  "deleteCancel": "Cancel"
}

Empty States

{
  "emptyExpenses": "No expenses yet",
  "emptyExpensesHint": "Tap + to add your first expense",
  "emptyGroups": "No groups yet",
  "emptyGroupsHint": "Create a group to start splitting expenses"
}