disable if no more items

I am working on getting this implemented into my app and I don't see if there is a way to disable this once someone has gotten to the bottom of the list. When that happens, I see in my android monitor it gets called repeatedly an unlimited number of times as long as the user near the bottom of the list.
Is there a way to turn it off once the last items have been loaded in, or should I just set the variable to null?