setProgressDrawable doesn't seem to work

When I use setDrawable, it doesn't seem to add the drawable to the dialog, 

```
 private var  progressDialog = ProgressDialog(this)
 progressDialog?.setCancelable(false)
 progressDialog?.setMessage("Logging in....")
 progressDialog?.setProgressDrawable(getDrawable(R.drawable.ic_truck_black_18dp))
 progressDialog?.show()
```
Not sure if I am doing something wrong....

Thanks.
