NotesActivity.kt

// Other stuff ...
    private lateinit var viewModelFactory: ViewModelFactory

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        initViews()

        viewModelFactory = ViewModelFactory(NotesRepository(this))

        listViewModel = ViewModelProviders.of(this, viewModelFactory).get(NotesListViewModel::class.java)
        listViewModel.allNotes.observe(this, Observer {
            noteAdapter.updateNotes(it)
        })
    }

// Other stuff ...

ViewModelFactory.kt

class ViewModelFactory(private val notesRepository: NotesRepository) : ViewModelProvider.Factory {

    override fun <T : ViewModel> create(modelClass: Class<T>): T =
        when {
            modelClass.isAssignableFrom(NotesListViewModel::class.java) ->
                    NotesListViewModel(notesRepository) as T

            modelClass.isAssignableFrom(EditorViewModel::class.java) ->
                    EditorViewModel(notesRepository) as T

            else -> throw IllegalArgumentException("ViewModel not found")
        }
}