title: Android: AutoCompleteTextView show suggestions when no text entered
body: <p>I am using <code>AutoCompleteTextView</code>, when the user clicks on it, I want to show suggestions even if it has no text - but <code>setThreshold(0)</code> works exactly the same as <code>setThreshold(1)</code> - so the user has to enter at least 1 character to show the suggestions.</p>