The lambda parameter in viewModels() method is a factory itself, so why google requires us to create a factory for the factory? Is it just an api fault or an intended decision?
I made a wrapper, which allows to pass parameters to the ViewModel much easier without creating a special factory. Are there any drawbacks of this solution?
class UserActivity {
val user by lazy { intent.getSerializableExtra("user") as User }
val viewModel by easyViewModels { UserViewModel(user) }
inline fun <reified T : ViewModel> easyViewModels(noinline factory: () -> T) = viewModels<T> {
object : ViewModelProvider.Factory {
override fun <S : ViewModel?> create(modelClass: Class<S>) = factory() as S
}
}
}
The reason for that is that I'm trying to integrate Dagger with Jetpack ViewModels. There is an another solution with multi binding: Inject property into ViewModel using Dagger 2, but it doesn't work with the assisted injection feature. So I made it the following way:
class UserActivity : AppCompatActivity() {
@Inject
lateinit var userViewModelFactory: UserViewModel.Factory
val user by lazy { intent.getSerializableExtra("user") as User }
val viewModel by easyViewModels { userViewModelFactory.create(user) }
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_user)
DaggerAppComponent.create().inject(this)
}
}
class UserViewModel @AssistedInject constructor(
val userUsecase: UserUsecase,
@Assisted val user: User
) : ViewModel() {
@AssistedFactory
interface Factory {
fun create(user: User): UserViewModel
}
}
Is it correct?
