Android :: ListView And ListAdapter

I am trying to use ListView and ListAdapter. If I create a simple Android project and add a ListView as the content view, and set it's adapter to my adapter based on ListAdapter, everything seems to work. My ListAdapter's 'getCount' is called, and I return 3, my 'getViewTypeCount' is called and I return 1, my 'getItemType' is called and I return 0, and for each item, my 'getView' is called and I return a TextView. Everything works, and the list is displayed with 3 items.

Now if I try and do the same thing in a more complicated environment, it does not work. My 'getCount', 'getViewTypeCount' and 'getItemType' methods are called, but the 'getView' method is never called and the ListView appears empty.

Now I know that I must be doing something wrong in the more complicated case, but I cannot see what it is. The code is really too involved to post here, but I was hoping that someone could give me some ideas as to why my 'getView' is never called even though I return 3 from my 'getCount' method.