title: How to check if an adapter filter doesn't correspond to any entries in a listview
body: <p>Does "getFilter().filter();" on a simple adapter have a way to check if a listview has that particular entry ?</p>
  
  <p>I have this code: </p>
  
  <pre><code>String tempString = searchField.getText().toString();
  
      if (tempString != "") {
           MainActivityFragment.adapter.getFilter().filter(tempString);
           MainActivityFragment.actionbar.setSubtitle("Search Results");
      }
  
      else {
  
          Toast.makeText(getActivity().getBaseContext(), "The Search Field can't be empty !", Toast.LENGTH_SHORT).show();
  
  
      }
  </code></pre>
  
  <p>I'd like to know if "filter(tempString);" is true (it exists in a particular listview). If not maybe prompt the user with a message.</p>