Android :: Add() Function Of Array Adapter Not Working

I have an ArrayAdapter (myAdapter) attached to an AutoCompleteTextView (textView)component. Once the user presses a character I would like to populate AutoCompleteTextView's drop down list with items containing this character. I retrieve the items using AsyncTask (which uses a web service).

I call myAdapter.add(item) but the drop down list is empty.I added a call myAdapter.getCount() after each addition and it shows zero every time.
Calling notifyDataSetChanged() didn't help.I even tried to add simple String objects instead of my custom objects, to no avail.What am I doing wrong?

Edit: I changed the code as miette suggested below but still to no avail.
Generally, what I do is after text is changed in my auto complete text view, I call a new AsyncTask and pass it the entered text and a Handler (see afterTextChanged()). The task retrieves objects relevant to the text and once done the Handler's handleMessage() is called. In handleMessage() I attempt to populate the adapter's objects. But still the adapter's drop down list ends up empty.

Here is my code:

public class AddStockView extends Activity implements OnClickListener, OnItemClickListener, TextWatcher {
ArrayAdapter<Stock> adapter;
AutoCompleteTextView textView;
Vector<Stock> stocks;
public AddStockView() {
// TODO Auto-generated constructor stub
stocks = new Vector<Stock>();}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.add_stock_view);
findViewById(R.id.abort_button).setOnClickListener(this);
adapter = new ArrayAdapter<Stock>(this,
android.R.layout.simple_dropdown_item_1line, stocks);
//adapter.setNotifyOnChange(true);
textView = (AutoCompleteTextView)
findViewById(R.id.search_edit_text);
textView.setAdapter(adapter);
textView.setOnItemClickListener(this);
textView.addTextChangedListener(this);} Code...