public void updateAll() {
   int itemId = 0;
   for (VideoItem videoItem : mVideoItems) {
     DownloadItemView itemView = (DownloadItemView) mParent.getChildAt(itemId);
     itemView.bind(videoItem);
     itemView.setItemId(itemId);
     itemView.setOnItemListener(this);
     itemId++;
   }
 }
 public void attachToParent(ViewGroup parent) {
   mParent = parent;
   parent.removeAllViews();
   int itemId = 0;
   for (VideoItem videoItem : mVideoItems) {
     DownloadItemView itemView = new DownloadItemView(parent.getContext());
     itemView.bind(videoItem);
     itemView.setItemId(itemId);
     itemView.setOnItemListener(this);
     parent.addView(itemView);
     itemId++;
   }
 }