lewisevans

class MyFragment : BaseFragment<MyViewModel>() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        viewModel = viewModelWith(activity!!)
        with(viewModel) {
          /*DO SOME STUFF HERE*/
        }
    }
}

lewisevans

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)

lewisevans

abstract class BaseActivity<VM : BaseViewModel> : DaggerAppCompatActivity() {

    @Inject
    internal lateinit var viewModelFactory: ViewModelFactory<VM>

    protected lateinit var viewModel:VM

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

lewisevans

class ViewModelFactory <T : ViewModel> @Inject constructor(private val viewModel: Lazy<T>) : ViewModelProvider.Factory {

    @Suppress("UNCHECKED_CAST")
    override fun <T : ViewModel?> create(modelClass: Class<T>): T = viewModel.get() as T
}