Per-app language preferences

In many cases, multilingual users set their system language to one language—such as English—but they want to select other languages for specific apps, such as Dutch, Chinese, or Hindi. To help apps provide a better experience for these users, Android 13 introduces the following features for apps that support multiple languages:

• System settings that let users select a preferred language for each app in a centralized location.

  Your app must declare the android:localeConfig attribute in your app's manifest to tell the system that it supports multiple languages. To learn more, see the instructions for creating a resource file and declaring it in your app's manifest file.

• APIs that let apps set a different language at runtime to use in their user interface.

  Apps that use custom in-app language pickers should use these new APIs to ensure that users have a consistent user experience regardless of where they select their language preferences. The new APIs also help you reduce the amount of boilerplate code, they support split APKs, and they support Auto Backup for Apps to store app-level user language settings.

  For backward compatibility with previous Android versions, APIs are also available in AndroidX. We recommend using Appcompat 1.6.0-alpha04 or higher.

Apps that do not support multiple languages are not impacted by these changes.

Overview of implementing this feature

The following table shows recommended implementations based on different use cases.

Use case	Recommended implementation
Your app doesn't have an in-app language picker	Use the android:localeConfig attribute in your app's manifest to add your app’s languages to phone settings. Optionally, if you want to add an in-app language picker: use the AndroidX library and opt in to our API implementation to support backward compatibility through autoStoreLocales.
Your app already has an in-app language picker	Use the android:localeConfig attribute in your app's manifest to add your app’s languages to phone settings. Migrate your app's custom logic to use the new APIs to ensure users see a consistent experience. Handle the following corner cases: Call AppCompatDelegate.setApplicationLocales() the first time your app is run on a device running Android 13. Call AppCompatDelegate.setApplicationLocales() to provide pre-existing user-requested locales to the system for the following cases: If you opt your app in to auto-storage for Android 12 (API level 32) and lower If your app needs to migrate data from a custom backup storage location

System settings for users

Android 13 adds a centralized location in phone settings for setting per-app language preferences. To ensure your app's languages are configurable in system settings on devices running Android 13, create a locales_config XML file and add it your app's manifest using the android:localeConfig attribute. Omitting the android:localeConfig manifest entry signals that users should not be able to set your app's language independent of their system language within their phone settings.

Important: If you run into unexpected behavior while testing this feature, check the current known issues related to the phone settings UI for possible causes.

Use android:localeConfig to add supported languages to phone settings

To add your app's supported languages to a user's phone settings:

1. Create a file called res/xml/locales_config.xml, and specify your app’s languages as follows:

   <?xml version="1.0" encoding="utf-8"?>
   <locale-config xmlns:android="http://schemas.android.com/apk/res/android">
      <locale android:name="ja"/>
      <locale android:name="fr"/>
      <locale android:name="en"/>
   </locale-config>
   

2. In the manifest, add a line pointing to this new file:

   <manifest
       ...
       <application
           ...
           android:localeConfig="@xml/locales_config">
       </application>
   </manifest>
   

How users select an app language in system settings

Users can select their preferred language for each app through the new system settings. They can access these settings in two different ways:

• Access through the System settings

  Settings > System > Languages & Input > App Languages > (select an app)

• Access through Apps settings

  Settings > Apps > (select an app) > Language

Known issues

There are a few known issues to keep in mind as you test your app.

• If you are using Android Gradle plugin (AGP) version 7.3.0-alpha07 through 7.3.0-beta02 or 7.4.0-alpha01 through 7.4.0-alpha03, you might encounter an issue that causes resource linking to fail when you declare android:localeConfig in your app's manifest file. This issue has been resolved in later versions of the AGP. If you are encountering this issue, use AGP 7.3.0-beta04 or later, AGP 7.4.0-alpha05 or later, or a prior AGP release.

Handle in-app language pickers

For apps that already have an in-app language picker or want to use one, use the new APIs instead of custom app logic to handle setting and getting a user's preferred language for your app.

For backward compatibility with previous Android versions, we strongly recommend using the AndroidX support library when implementing an in-app language picker. However, you can also implement the framework APIs directly if you need to.

Implement using the AndroidX support library

Use the setApplicationLocales() method in Appcompat 1.6.0-alpha04 or higher.

For example, to set a user's preferred language, you would ask the user to select a locale in the language picker, then set that value in the system:

Kotlin

val appLocale: LocaleListCompat = LocaleListCompat.forLanguageTags("xx-YY")
// Call this on the main thread as it may require Activity.restart()
AppCompatDelegate.setApplicationLocales(appLocale)

Java

LocaleListCompat appLocale = LocaleListCompat.forLanguageTags("xx-YY");
// Call this on the main thread as it may require Activity.restart()
AppCompatDelegate.setApplicationLocales(appLocale);

Support Android 12 and lower

To support for devices running Android 12 (API level 32) and lower, tell AndroidX to handle locale storage by setting an autoStoreLocales value to true and android:enabled to false in the manifest entry for your app's AppLocalesMetadataHolderService service, as shown in the following code snippet:

<application
  ...
  <service
    android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
    android:enabled="false"
    android:exported="false">
    <meta-data
      android:name="autoStoreLocales"
      android:value="true" />
  </service>
  ...
</application>

Note that setting an autoStoreLocales value to true causes a blocking read on the main thread and might cause a StrictMode diskRead and diskWrite violation if you are logging thread violations. See AppCompatDelegate.setApplicationLocales() for more information.

Custom storage handling

Omitting the manifest entry or setting autoStoreLocales to false signals that you are handling your own storage. In this case, you must provide the stored locales before onCreate in the activity lifecycle and gate calls to AppCompatDelegate.setApplicationLocales() in Android 12 (API level 32) or lower.

If your app has a custom locale storage location, we recommend using a one-time handoff between your custom locale storage solution and autoStoreLocales so users continue to enjoy your app in the language they prefer. This is especially applicable in cases when your app is first run after a device has upgraded to Android 13. In this case, you can provide pre-existing user-requested locales by retrieving the locales from your custom storage and passing the locales into AppCompatDelegate.setApplicationLocales().

Implement using the Android framework APIs

While we strongly recommend that you use the AndroidX support library to implement in-app language pickers, you can also use the setApplicationLocales() and getApplicationLocales() methods in the Android framework for devices running Android 13.

For example, to set a user's preferred language, you would ask the user to select a locale in the language picker, then set that value in the system:

// 1. Inside an activity, in-app language picker gets an input locale "xx-YY"
// 2. App calls the API to set its locale
mContext.getSystemService(LocaleManager.class
    ).setApplicationLocales(newLocaleList(Locale.forLanguageTag("xx-YY")));
// 3. The system updates the locale and restarts the app, including any configuration updates
// 4. The app is now displayed in "xx-YY" language

To get a user's current preferred language to display in the language picker, your app can get the value back from the system:

// 1. App calls the API to get the preferred locale
LocaleList currentAppLocales =
    mContext.getSystemService(LocaleManager.class).getApplicationLocales();
// 2. App uses the returned LocaleList to display languages to the user

Additional best practices

Take note of the following best practices.

Consider language when invoking an intent in another app

Language-focused intents might allow you to specify the language you want the invoked app to be in. One example is the Speech Recognizer API’s EXTRA_LANGUAGE feature.

Consider the Accept-Language header for Chrome Custom tab

Consider adding the Accept-Language Header through the Browser.EXTRA_HEADERS to open a web page in your app's language when invoking a Chrome Custom tab.