title: Don't work showDropDown on AutocompleteTextView
body: <p>I'm using AutocompleteTextView. the showDropDown function does not work. How do I activate this function? how do I run showdropdown? I need to do?</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener, OnItemSelectedListener, View.OnTouchListener, RadioGroup.OnCheckedChangeListener{
       private static final String[] paths = {"...."};
   @Override
      protected void onCreate(Bundle savedInstanceState) {
  
   final ArrayAdapter&lt;String&gt; arrayAdapterLocation = new ArrayAdapter&lt;String&gt;(getApplicationContext(), android.R.layout.simple_spinner_dropdown_item,paths);
  
  final AutoCompleteTextView textViewLocationUpdate;        textViewLocationUpdate = (AutoCompleteTextView) findViewById(R.id.txtlocationUpdate);
    textViewLocationUpdate.setOnTouchListener(new OnTouchListener() {
  
              @SuppressLint("ClickableViewAccessibility")
              @Override
              public boolean onTouch(View paramView, MotionEvent paramMotionEvent) {
                  // TODO Auto-generated method stub
                  textViewLocationUpdate.showDropDown();
                  textViewLocationUpdate.requestFocus();
                  return false;
              }
          });
          textViewLocationUpdate.setOnItemClickListener(new OnItemClickListener() {
  
              @Override
              public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) {
  
   final String selected = (String) parent.getItemAtPosition(position);
   final Object item = parent.getItemAtPosition(position);
          refDeviceName.child("title").addListenerForSingleValueEvent(new ValueEventListener() {
                      @Override
                      public void onDataChange(DataSnapshot dataSnapshot) { dataSnapshot.getRef().setValue(selected); }
                      @Override
                      public void onCancelled(DatabaseError databaseError) { }});  }
          });
  </code></pre>