listview not refreshing

package com.conceptualsystems.kitmobile;

import java.util.*;

import android.app.*;
import android.os.*;
import android.content.*;
import android.widget.*;
import android.view.*;
import android.util.Log;

public class ShipActivity extends Activity
{
    //UI elements
    private ListView mShipKitListView;
    private LayoutInflater mInflater;
    private SharedPreferences mPrefs;
    private List<Map<String, String>> mShipKitList;
    private SimpleAdapter mShipKitAdapter;

    //constants
    private String LOG_TAG = "KitMobile - ShipActivity.java";

    /** inner classes **/
    public class ShipKitAdapter extends BaseAdapter {
        private LayoutInflater mInflater;
        private List<Map<String, String>> mData;

        public ShipKitAdapter(Context context, List<Map<String, String>> data) {
            mInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            mData = data;
        }

        public long getItemId(int position) {
            return position;
        }

        public Object getItem(int position) {
            return mData.get(position);
        }

        public int getCount() {
            return mData.size();
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if(convertView==null) {
                convertView = mInflater.inflate(R.layout.ship_list_item, null);
            }
            ((TextView)convertView.findViewById(R.id.kit_id)).setText(mData.get(position).get("kit_id"));
            ((TextView)convertView.findViewById(R.id.net_units)).setText(mData.get(position).get("net_units"));
            ((TextView)convertView.findViewById(R.id.net_uom)).setText(mData.get(position).get("net_uom"));
            ((TextView)convertView.findViewById(R.id.product_name)).setText(mData.get(position).get("product_name"));
            ((TextView)convertView.findViewById(R.id.gross_units)).setText(mData.get(position).get("gross_units"));
            ((TextView)convertView.findViewById(R.id.gross_uom)).setText(mData.get(position).get("gross_uom"));
            return convertView;
        }
    };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        mPrefs = getSharedPreferences("kitmobileprefs", Context.MODE_PRIVATE);
        mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        //data init
        mShipKitList = new ArrayList<Map<String, String>>();

        initScreen();
    }

    private void initScreen() {
        setContentView(R.layout.ship);
        mShipKitListView = (ListView)findViewById(R.id.kit_list);
        mShipKitAdapter = new SimpleAdapter(
                this,
                mShipKitList,
                R.layout.ship_list_item,
                new String[] { "kit_id","net_units","net_uom","gross_units","gross_uom","product_name" },
                new int[] { R.id.kit_id, R.id.net_units, R.id.net_uom, R.id.gross_units, R.id.gross_uom, R.id.product_name }
            );
        mShipKitListView.setAdapter(mShipKitAdapter);
    }

    private void addFakeListItem(String id) {
        int position = mShipKitList.size();
        mShipKitList.add(new HashMap<String, String>());
        mShipKitList.get(position).put("kit_id", id);
        mShipKitList.get(position).put("net_units", "5027");
        mShipKitList.get(position).put("net_uom", "lbs");
        mShipKitList.get(position).put("gross_units", "5155");
        mShipKitList.get(position).put("gross_uom", "lbs");
        mShipKitList.get(position).put("product_name", "COPPER #1");

        //mShipKitAdapter.notifyDataSetInvalidated();
        mShipKitAdapter.notifyDataSetChanged();
        //mShipKitListView.invalidate();
    }

    // OPTIONS MENU
    ///////////////
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.ship_options, menu);
        return true;
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch(item.getItemId()) {
            case R.id.opt_add_item:
                //add a fake item to the list
                Random gen = new Random();
                addFakeListItem(new Integer(gen.nextInt(5000)).toString());
                Log.i(LOG_TAG, mShipKitList.toString());
                return true;
            case R.id.opt_transmit:
                mShipKitAdapter.notifyDataSetChanged();
                //mShipKitAdapter.notifyDataSetInvalidated();
                //Log.i(LOG_TAG, mShipKitList.toString());
                //((ArrayAdapter)mShipKitListView.getAdapter()).notifyDataSetChanged();
                //mShipKitListView.invalidate();
                return true;
            default:
                super.onOptionsItemSelected(item);
                return true;
        }
    }
}