- name
- localization-setup
- description
- Generate internationalization (i18n) infrastructure for multi-language support in iOS/macOS apps. Use when localizing for multiple languages, adopting String Catalogs (xcstrings), or supporting RTL languages.
- allowed-tools
- ["Read","Write","Edit","Glob","Grep","Bash","AskUserQuestion"]
- last_verified
- 2026-07-16T00:00:00.000Z
- review_by
- 2027-06-22T00:00:00.000Z
- os_version
- iOS 27 / macOS 27
# Localization Setup Generator
Generate internationalization (i18n) infrastructure for multi-language support in iOS/macOS apps.
## When This Skill Activates
- User wants to localize their app for multiple languages
- User mentions i18n, internationalization, or localization
- User asks about String Catalogs or .strings files
- User wants to support RTL (right-to-left) languages
## Pre-Generation Checks
Before generating, verify:
1. **Existing Localization**
```bash
# Check for existing localization files
find . -name "*.xcstrings" -o -name "Localizable.strings" 2>/dev/null | head -5
find . -name "*.lproj" -type d 2>/dev/null | head -5
```
2. **Deployment Target**
```bash
# String Catalogs require iOS 16+ / macOS 13+
grep -r "IPHONEOS_DEPLOYMENT_TARGET\|MACOSX_DEPLOYMENT_TARGET" *.xcodeproj 2>/dev/null
```
3. **Project Structure**
```bash
# Find project for adding localization
find . -name "*.xcodeproj" | head -1
```
## Configuration Questions
### 1. Localization Approach
- **String Catalogs** (Recommended, iOS 16+) - Modern, visual editor in Xcode
- **Legacy .strings** - Traditional approach, all iOS versions
### 2. Initial Languages
- English (en) - default
- Which additional languages? (e.g., es, de, fr, ja, zh-Hans)
### 3. Features
- **Pluralization** - Handle "1 item" vs "2 items"
- **Device-specific** - Different strings for iPhone/iPad/Mac
- **SwiftUI Preview** - Preview in different locales
## Generated Files
### String Catalogs (Recommended)
```
Resources/
└── Localizable.xcstrings # String catalog with all translations
```
### Supporting Code
```
Sources/Localization/
├── LocalizedStrings.swift # Type-safe string access
├── LocalizationManager.swift # Runtime language switching
└── LocalizedPreview.swift # SwiftUI preview helpers
```
## Key Features
### Type-Safe String Access
```swift
// Generated enum for type-safe access
enum L10n {
static let appName = String(localized: "app_name")
static let welcomeMessage = String(localized: "welcome_message")
enum Settings {
static let title = String(localized: "settings_title")
static let language = String(localized: "settings_language")
}
}
// Usage
Text(L10n.appName)
Text(L10n.Settings.title)
```
### Pluralization
```swift
// In String Catalog, define plural rules
// key: "items_count"
// variations:
// - zero: "No items"
// - one: "1 item"
// - other: "%lld items"
Text(String(localized: "items_count \(count)",
defaultValue: "\(count) items"))
```
### String Interpolation
```swift
// In String Catalog:
// key: "greeting"
// value: "Hello, %@!"
let name = "Alice"
Text(String(localized: "greeting \(name)"))
```
### Runtime Language Switching
```swift
// Preview in different locale
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
.environment(\.locale, Locale(identifier: "es"))
}
}
```
## Integration Steps
### 1. Add String Catalog
1. In Xcode: File > New > File
2. Choose "String Catalog"
3. Name it "Localizable.xcstrings"
4. Add to your app target
### 2. Add Supported Languages
1. Select project in navigator
2. Info tab > Localizations
3. Click + to add languages
### 3. Migrate Existing Strings
If migrating from .strings files:
1. Right-click .strings file
2. "Migrate to String Catalog..."
### 4. Use in SwiftUI
```swift
// Automatic localization
Text("Hello, World!") // Uses String Catalog automatically
// Explicit localized string
Text(String(localized: "custom_key"))
// With type-safe enum (generated)
Text(L10n.welcomeMessage)
```
### 5. Use in UIKit
```swift
label.text = String(localized: "hello_world")
// or
label.text = NSLocalizedString("hello_world", comment: "Greeting")
```
## Best Practices
### Key Naming Conventions
```
// Good: Descriptive, hierarchical
"settings.appearance.theme"
"onboarding.step1.title"
"error.network.connection_failed"
// Avoid: Vague or hardcoded text as key
"button1"
"Hello, World!"
```
### Comments for Translators
```swift
String(localized: "delete_confirmation",
comment: "Alert message asking user to confirm deletion")
```
### Formatting
```swift
// Numbers - Use FormatStyle
Text(price, format: .currency(code: "USD"))
// Dates - Use FormatStyle
Text(date, format: .dateTime.month().day())
// Lists - Use ListFormatStyle
Text(items, format: .list(type: .and))
```
### RTL Support
```swift
// Automatic with SwiftUI
// For manual layout adjustments:
.environment(\.layoutDirection, .rightToLeft)
```
## Testing Localization
### In Xcode
1. Edit Scheme > Run > Options
2. Set "App Language" to test language
3. Set "App Region" for number/date formatting
### In SwiftUI Previews
```swift
#Preview {
ContentView()
.environment(\.locale, Locale(identifier: "ja"))
}
```
### Export for Translation
1. Product > Export Localizations...
2. Share .xliff files with translators
3. Import translated .xliff files
## References
- [String Catalogs](https://developer.apple.com/documentation/xcode/localizing-and-varying-text-with-a-string-catalog)
- [Localization Guide](https://developer.apple.com/localization/)
- [Formatting Numbers and Dates](https://developer.apple.com/documentation/foundation/formatstyle)
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