Adapter notfiyDataSetChanged not working in ListFragment

Adapter notfiyDataSetChanged not working in ListFragment

I am trying to add items to my list view when a user scrolls to the bottom
of the page. I am trying to add items to the array in an AsyncTask then
use notifyDataSetChanged on the existing adapter to display the new items,
but it doesn't seem to work. However, it does work if I create a new
adapter after adding the items, but this causes a jump to the top of the
list, and is also probably bad practice? Any ideas what I am doing wrong.
Here is my code:
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
return (LinearLayout)inflater.inflate(R.layout.tab1, container, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
View footerView =
((LayoutInflater)getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.list_footer,
null, false);
this.getListView().addFooterView(footerView);
items.add(new HomeListItem(1,
getResources().getDrawable(R.drawable.test), "Item Description Here",
testImages));
items.add(new HomeListItem(2,
getResources().getDrawable(R.drawable.test), "Item Description Here",
testImages));
items.add(new HomeListItem(3,
getResources().getDrawable(R.drawable.test), "Item Description Here",
testImages));
items.add(new HomeListItem(4,
getResources().getDrawable(R.drawable.test), "Item Description Here",
testImages));
items.add(new HomeListItem(5,
getResources().getDrawable(R.drawable.test), "Item Description Here",
testImages));
//Populate list view with array objects
adapter = new HomeListItemAdapter(getActivity(), 1, items);
listView = getListView();
listView.setAdapter(adapter);
listView.setOnScrollListener(this);
}
public void onScroll(AbsListView view, int firstVisibleItem, int
visibleItemCount, int totalItemCount) {
int lastInScreen = (firstVisibleItem + visibleItemCount);
if ((lastInScreen == totalItemCount) && !(loadingMore)) {
new addItem().execute();
}
}
private class addItem extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
loadingMore = true;
}
@Override
protected void onPostExecute(Void arg3) {
Toast toast = Toast.makeText(getActivity(), "ADD ITEM",
Toast.LENGTH_SHORT);
toast.show();
adapter.notifyDataSetChanged();
//int currentPosition = listView.getFirstVisiblePosition();
//setListAdapter(new HomeListItemAdapter(getActivity(), 1, items));
loadingMore = false;
}
@Override
protected Void doInBackground(Void... params) {
for (int i=0; i<3; i++) {
items.add(new HomeListItem((items.size()+i),
getResources().getDrawable(R.drawable.logo), "NEW ITEM " +
(i),
testImages));
}
return null;
}
}
// Custom list item class for menu items
public class HomeListItemAdapter extends ArrayAdapter<HomeListItem> {
private List<HomeListItem> items;
private Context context;
private int numItems = 0;
private ImageView image1;
private ImageView image2;
private ImageView image3;
static class ViewHolder {
ImageView sourceImage;
TextView itemName;
ImageView itemImage1;
ImageView itemImage2;
ImageView itemImage3;
ImageView itemImage4;
ImageView itemImage5;
}
public HomeListItemAdapter(Context context, int id, List<HomeListItem>
items) {
super(context, id, items);
this.items = items;
this.context = context;
this.numItems = items.size();
}
public int getCount() {
return numItems;
}
public HomeListItem getItem(int position) {
return items.get(position);
}
public long getItemId(int position) {
return items.indexOf(getItem(position));
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
LayoutInflater inflater = LayoutInflater.from(context);
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_item, null);
//Set up ViewHolder for item caching purposes
holder = new ViewHolder();
holder.sourceImage = (ImageView)
convertView.findViewById(R.id.source_image);
holder.itemName = (TextView)
convertView.findViewById(R.id.item_description);
holder.itemImage1 = (ImageView)
convertView.findViewById(R.id.item_image);
holder.itemImage2 = (ImageView)
convertView.findViewById(R.id.item_image2);
holder.itemImage3 = (ImageView)
convertView.findViewById(R.id.item_image3);
holder.itemImage4 = (ImageView)
convertView.findViewById(R.id.item_image4);
holder.itemImage5 = (ImageView)
convertView.findViewById(R.id.item_image5);
//Set holder tag
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
//Set item elements
holder.sourceImage.setImageDrawable(items.get(position).getSourcePic());
holder.itemName.setText(items.get(position).getText());
//Get ArrayList of item images
ArrayList<Bitmap> itemImages = items.get(position).getItemImages();
//Set ImageView bitmaps (Load in AsyncTask)
holder.itemImage1.setImageBitmap(itemImages.get(0));
holder.itemImage2.setImageBitmap(itemImages.get(1));
holder.itemImage3.setImageBitmap(itemImages.get(2));
holder.itemImage4.setImageBitmap(itemImages.get(3));
holder.itemImage5.setImageBitmap(itemImages.get(4));
return convertView;
}