BaseFragment.kt

abstract class BaseFragment<VM : BaseViewModel> : DaggerFragment() {

    @Inject
    internal lateinit var viewModelFactory: ViewModelFactory<VM>

    protected lateinit var viewModel: VM

    internal inline fun <reified VM : ViewModel> viewModelWith(frag: Fragment): VM =
        ViewModelProviders.of(frag, viewModelFactory).get(VM::class.java)

    internal inline fun <reified VM : ViewModel> viewModelWith(act: FragmentActivity): VM =
        ViewModelProviders.of(act, viewModelFactory).get(VM::class.java)

}

Use it in Fragment like: viewModel = viewModelWith(activity!!) and it's automatically cast