Naive implementation of Swipe-to-Refresh with LiveData

UserListActivity.kt

// DON'T DO THIS
class UserListActivity : AppCompatActivity() {

    @Inject internal lateinit var viewModelFactory: ViewModelProvider.Factory
    private lateinit var userListViewModel: UserListViewModel
    private lateinit var swipeRefreshLayout: SwipeRefreshLayout

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

        userListViewModel = ViewModelProviders.of(this, viewModelFactory).get(UserListViewModel::class.java)

        setUpUi()
        fetchUsers()
    }

    private fun setUpUi() {
        swipeRefreshLayout = findViewById(R.id.user_list_swipe_refresh_layout)
        swipeRefreshLayout.setOnRefreshListener {
            userListViewModel.getUsers()
        }
    }

    private fun fetchUsers() {
        swipeRefreshLayout.isRefreshing = true
        userListViewModel.getUsers().observe(this, Observer { users -> users?.let { displayUsers(it) } })
    }

    private fun displayUsers(users: List<UserModel>) {
        swipeRefreshLayout.isRefreshing = false
        // Display users...
    }
}