title: listview header with large image
body: <p>I have a listview which headerView has a large image. When I call </p>
  
  <pre><code>listView.addHeaderView(headerView)
  </code></pre>
  
  <p>my listview doesn't scroll smoothly when I remove it it start scroll fine. </p>
  
  <p>I am using Aquery lib for downloading image and cashing image</p>
  
  <pre><code>AQuery aq = new AQuery(img);
          aq.id(R.id.image).image(mProduct.getMobile_pic(), true, true, mActivity.getCurrentDeviceDisplayMatrics().widthPixels, 0, new BitmapAjaxCallback(){
  
              @Override
              public void callback(String url, ImageView iv, Bitmap loadedImage, AjaxStatus status){
                  iv.setImageBitmap(loadedImage);
              }
  
          });
  </code></pre>
  
  <p>first true value is turn on memory cache, second is disk cache.</p>
  
  <p>What possible reason could prevent smooth scroll of listview? </p>