Hilt Inject into ViewModel without constructor params

Question

With the new dependency injection library Hilt, how to inject some classes into ViewModel without constructor params and ViewModelFactory? Is it possible?

Like in Fragment, we use only @AndroidEntryPoint and @Inject.

Answer 1

how to inject some classes into ViewModel without constructor params and ViewModelFactory? Is it possible?

Hilt supports constructor injection of ViewModel via the @HiltViewModel (previously @ViewModelInject) annotation.

This allows for any @AndroidEntryPoint-annotated class to redefine their defaultViewModelProviderFactory to be the HiltViewModelFactory, which allows the creation of @HiltViewModel-annotated ViewModels correctly instantiated via Dagger/Hilt.

NEW HILT VERSION:

@HiltViewModel
class RegistrationViewModel @Inject constructor(
    private val someDependency: SomeDependency,
    private val savedStateHandle: SavedStateHandle
) : ViewModel() {
    ...
}

OLD HILT VERSION:

class RegistrationViewModel @ViewModelInject constructor(
    private val someDependency: SomeDependency,
    @Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
    ...
}

---

And then

@AndroidEntryPoint
class ProfileFragment: Fragment(R.layout.profile_fragment) {
    private val viewModel by viewModels<RegistrationViewModel>() // <-- uses defaultViewModelProviderFactory