MyActivity.kt

class MyActivity: Activity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setupViewModel()
  }
  private fun setupViewModel() {
     viewModel = //factory fancy way to get the instance of ViewModel
     viewModel.viewState.observe(this, Observer {
       when (it) {
         MVIViewState.Loading -> { // show loading
         }
         MVIViewState.Error -> { // display error message
         }
         MVIViewState.Success -> { // show data fetched
         }
       }
     )
  }
}