This snippet demonstrates a better way to inject constant values using Hilt in Android. Instead of relying on a centralized Constants.kt file and @nAmed strings (which are error-prone and hard to refactor), it uses custom @qualifier annotations. This approach provides compile-time safety, clearer dependency injection, and easier maintenance.

constants.kt

@Qualifier
@Retention(AnnotationRetention.BINARY)
annotation class SharedPreferencesFileNameKey

@Qualifier
@Retention(AnnotationRetention.BINARY)
annotation class LanguageCodeKey

@Module
@InstallIn(SingletonComponent::class)
object DataStoreKeyModule {

    @Provides @SharedPreferencesFileNameKey
    fun provideSharedPreferencesFileName() = "sample_shared_prefs"

    @Provides @LanguageCodeKey
    fun provideLanguageCodeKey() = "app_language_code"

    // ... and provides for every other qualifier
}

@HiltViewModel
class MyViewModel @Inject constructor(
    @LanguageCodeKey private val languageCodeKey: String,
    @CurrentUserDetailsKey private val userDetailsKey: String
) : ViewModel() {
    // ...
}