MainActivity
For now, extend from AppCompatActivity. Otherwise, setApplicationLocales will do nothing.
Extending from AppCompatActivity requires to use an AppCompat theme for the Activity. In the manifest, for the activity, use android:theme="@style/Theme.AppCompat" Otherwise, the application will crash.
The alternative is to replace AppCompatDelegate with the Framework APIs. The Frameworks APIs are not backwards compatible, like AppCompatDelegate, and so work for T+. However, with the Framework APIs, you can use Compose themes and extend from ComponentActivity. Framework APIs: https://developer.android.com/about/versions/13/features/app-languages#framework-impl Read more: https://developer.android.com/guide/topics/resources/app-languages#gradle-config