I have also this problem, I think it seems to be a bug, i solved this by the following way
It shows dropdown list automatically, only when the view is in focusable state which is annoying to user, otherwise it works good.
Second change your AutoCompleteTextView focusable property to true in onTouch event of that view.For that you have to implement onTouchListener to the AutoCompleteTextview.
Whenever you touching on that AutoCompleteTextView, you should change focusable property to true otherwise keep it focusable to false. So that the dropdown list is never appear when the view is in unfocusable state.