Internationalization

What it provides

Key files

How switching works

LocaleController maps the DataStore language_tag string into an AppLanguage:

enum class AppLanguage(val tag: String, val labelResId: Int) {
    English("en", R.string.language_english),
    Chinese("zh", R.string.language_chinese)
}

MainActivity wraps the app with LocalizedAppHost. The host creates a localized Context using Locale.forLanguageTag(language.tag), then provides that context and configuration through Compose locals:

LocaleController.selectedLanguage
  -> LocalizedAppHost
  -> LocalContext / LocalConfiguration
  -> stringResource(...)

Because the localized context is provided inside the composition, changing the language updates visible Compose strings in-session without an activity restart.

Resource rule

Put all user-visible copy in resources:

<string name="notifications_title">Notifications</string>

Then read it from Compose:

Text(stringResource(R.string.notifications_title))

Avoid hardcoding screen labels, button text, validation messages, and demo copy inside composables. The current Component gallery catalog is one area to audit if you want every demo title and summary localized too: its catalog entries are plain Kotlin strings.

Add a language

app/src/main/res/values-ja/strings.xml

Japanese("ja", R.string.language_japanese)

Verify

• Every key in values/strings.xml exists in values-zh/strings.xml.
• No product-facing copy is hardcoded in feature screens.
• The drawer language picker persists across app restarts.
• Switching language updates nested screens and dialogs, not only top-level tabs.
• Release-only strings such as Play review notes and legal URLs are handled outside the APK where appropriate.

Related pages