String Catalogとローカライズ文字列

そもそもなぜローカライズするのか

// Hardcoded — bad for localization
// let title = "Welcome"

// Localized — looked up by key
let title = String(localized: "Welcome")

String Catalog

// Localizable.xcstrings holds entries like:
// key: "Welcome"
//   en: "Welcome"
//   tr: "Hos geldiniz"
//   ja: "Yokoso"

String(localized:)

let greeting = String(localized: "Welcome back")
let cancel = String(localized: "Cancel")
print(greeting)

翻訳者向けのコメントを追加する

let runLabel = String(
    localized: "Run",
    comment: "Button that executes the user's code")

値を埋め込む

let name = "Mira"
let count = 3
let msg = String(localized: "\(name) has \(count) new messages")
print(msg)

SwiftUIでのLocalizedStringKey

// In SwiftUI — the literal is a LocalizedStringKey
// Text("Welcome back")        // auto-localized
// Button("Save") { save() }   // auto-localized
let key: LocalizedStringKey = "Welcome back"
_ = key

意図しないローカライズを避ける

let userInput = "hello"
// Text(userInput)            // NOT a localization key
// Text(verbatim: userInput)  // explicitly raw, never localized
let verbatimKey = userInput
_ = verbatimKey

テーブルを指定する

let onboardingTitle = String(
    localized: "Get Started",
    table: "Onboarding",
    bundle: .main)

LocalizedStringResource

let resource = LocalizedStringResource("Order shipped")
// Resolve later, possibly in another locale context
let resolved = String(localized: resource)
print(resolved)

デフォルトのローカライズ

// If only 'en' is translated and device is set to 'fr',
// the development-language value is shown as fallback.
let fallback = String(localized: "Settings")
print(fallback)

実用的な検索例

func welcomeMessage(for user: String) -> String {
    return String(
        localized: "Welcome, \(user)!",
        comment: "Greeting shown after sign-in")
}
print(welcomeMessage(for: "Ada"))

クイックチェック

まとめ