Universal image loader not work

I'm a beginning programmer. I'm trying use Universal image loader to display images parsed from site, but it is not work. What am I doing wrong? Thanks. This is a test programm. ``` package com.example.imageloader; public class MainActivity extends ListActivity { private final String URL = "Site_URL"; private ArrayList<Order> listItems = null; private myAdapter myAdapter; private ProgressDialog pd; ImageLoader imageLoader; DisplayImageOptions options; String imgSrc; ListView lv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listItems = new ArrayList<Order>(); this.myAdapter = new myAdapter(this, R.layout.list_item, listItems); setListAdapter(this.myAdapter); new Parse().execute(URL); lv = getListView(); imageLoader = ImageLoader.getInstance(); imageLoader.init(ImageLoaderConfiguration.createDefault(MainActivity.this)); options = new DisplayImageOptions.Builder() .showStubImage(R.drawable.ic_launcher) .showImageForEmptyUri(R.drawable.ic_launcher) .cacheOnDisc() .cacheInMemory() .build(); } private class Parse extends AsyncTask<String, Integer, ArrayList<Order>> { @Override protected void onPreExecute() { pd = new ProgressDialog(MainActivity.this); pd.setMessage("Loading"); pd.show(); } @Override protected ArrayList<Order> doInBackground(String... urls) { listItems.clear(); try { Document doc = Jsoup.connect(URL).get(); Elements img = doc.select("img"); for (Element src : img) { String imgSrc = src.attr("src"); System.out.println(imgSrc); Order o = new Order(); o.setLink(imgSrc); o.setTextName(imgSrc); listItems.add(o); } } catch (IOException e) { e.printStackTrace(); } return listItems; } @Override protected void onPostExecute(ArrayList<Order> listItems) { myAdapter = new myAdapter(MainActivity.this, R.layout.list_item, listItems); setListAdapter(myAdapter); myAdapter.notifyDataSetChanged(); pd.dismiss(); } } } ``` Custom adater I get an error here ``` package com.example.imageloader; public class myAdapter extends ArrayAdapter<Order> { private LayoutInflater lInflater; private ArrayList<Order> data; DisplayImageOptions options; ImageLoader imageLoader; private Order o; String imgSrc; public myAdapter(Context c, int listItem, ArrayList<Order> data) { super(c, listItem, data); this.data = data; lInflater = LayoutInflater.from(c); } public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; if (convertView == null) { convertView = lInflater.inflate(R.layout.list_item, null); holder = new ViewHolder(); holder.img = (ImageView) convertView.findViewById(R.id.image); holder.textName = (TextView) convertView.findViewById(R.id.text); convertView.setTag(holder); holder.textName.setOnClickListener(new OnItemClickListener(position)); } else { holder = (ViewHolder) convertView.getTag(); } o = data.get(position); holder.textName.setText(o.getTextName()); holder.img.setTag(o); try { imageLoader.displayImage(o.getLink(), holder.img, options); // NullPointerException here! } catch (NullPointerException e) { e.printStackTrace(); } } else { return null; } return convertView; static class ViewHolder { ImageView img; TextView textName; } } ``` Log ``` 01-16 11:55:04.480: W/System.err(19105): java.lang.NullPointerException 01-16 11:55:04.496: W/System.err(19105): at com.example.imageloader.myAdapter.getView(myAdapter.java:62) ```