title: v.getTag() returns null instead of ViewHolder
body: <p>I have a customized adapter that has a header and customized rows. Sometimes my v.getTag() returns null where I have stored my ViewHolder. It does not happen all the times and I can not figure out when and why it accurs. </p>
  
  <pre><code>@Override
  public View getView(int position, View convertView, ViewGroup parent) {
      View v = convertView;
  
      //Header
      if(items.hasDescription() &amp;&amp; 0 == position) {
          LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
          v = vi.inflate(R.layout.app_list_header, null); 
          ((TextView) v.findViewById(R.id.app_list_header_description_text)).setText(items.getDescription());
          return v;
      }
  
      ViewHolder holder;
      // Inflate app view.
      if (v == null || v.getTag() == null) {
          LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
          v = vi.inflate(textViewResourceId, null); //TODO: parent instead of null?
          holder = new ViewHolder();
          holder.title = (TextView) v.findViewById(R.id.title);
          holder.company = (TextView) v.findViewById(R.id.company);
          holder.priceOrStatus = (TextView) v.findViewById(R.id.price);
          holder.rating = (RatingBar) v.findViewById(R.id.rating);
          holder.icon = (ImageView) v.findViewById(R.id.icon);
          v.setTag(holder);
      } else {
          holder = (ViewHolder) v.getTag();
      }
  
  }
      App app;
      if(items.hasDescription()) {
          app = items.get(position-1);    
      } else {
          app = items.get(position);
      }
  
      // TODO: Do we need this?
      if (null == app || null == holder) {
          Log.d(TAG, "app: " +app +" holder: " +holder);
          return v;
      }
  
      //TODO: FIX THE XML BEFORE SO WE DO NOT NEED TO TRIM IT.
      // And get rid of all these ifs!!
      if(holder.title != null) {
          holder.title.setText(app.getTitle().trim());                            
  
      }
  </code></pre>
  
  <p>Can anyone help me out?</p>