In Android\'s ListView widget, the ListView will hold the views which is got from getView method of an Adapter in a inner class
If I remember correctly a call to invalidate on a ListView widget will empty the cache of Views which are currently stored. I would advise against emptying the cache of views of a ListView because of the potential performance issues.
If you're not going to use the convertView item then you'll end up with having to build the row view each time(resulting in a lot of objects constructed each time the user scrolls) + the extra memory occupied by the recycled views from the RecycleBin which will never be used anyway.