title: RecyclerView - bind the view holders again
body: <p>TL,DR : How can I force the recycler view to call the onBindViewHolder method again, at least for the visible items?</p>
  
  <p>Calling notifyDataSetChanged() will make the list lag for some milliseconds, is there a better way?
  Thanks.</p>
  
  <p>I have a layout with an ImageView.
  When ever bind is called for the imageview, I send a request to a server in order to get an image.
  When the image is loaded, I save the bitmap in the ViewHolder , T variable.
  And in the bind method I check if variable.getBitmap() is null or not, and if it is I will set the imageview.
  Now If I scroll my list the images are going to be loaded, but If not, the imageviews are still blank, because onBindViewHolder wasn't called again.</p>
  
  <p>Thanks.</p>