I was stuck on this for a little while since it wasn’t updated in the documentation and also since I am still a newbie at Kotlin ;)

class PopularActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        listView {

            id = ViewID.ID_POPULAR_LIST

          // This task will happen asynchronously in a separate thread (so you can perform network operations)
          // and the returned value can be accessed through the Future object
          // f.get() blocks till the task is finished
            fun getTitles() : ArrayList<String> {
                val arr = ArrayList<String>()
                // add elements to list
                return arr
            }

          // so yeah, this is the tricky part (for me at least) since it wasn't updated in the documentation. Enjoy! :)
            val m: (AnkoAsyncContext<ListView>.() -> ArrayList<String>) = {
                ::getTitles.invoke()
            }
            val f : Future<ArrayList<String>> = doAsyncResult(null, m)

            adapter = ArrayAdapter<String>(ctx, android.R.layout.simple_list_item_1, f.get())
        }
    }
}

Some of the description has been already added in the code, as you can see. Let me explain the premise of this solution in any case. The problem arose because I had to perform a network task in the onCreate method and as you know we can’t normally perform a network task in the uiThread. Luckily, Anko provides an elegant solution to this without having the need to implement an AsyncTask interface. doAsync runs whatever task you give it but does not return anything. However, although doAsyncResult is similar to doAsync it can additionally return an object.

A Merry Christmas to you!