There doesn't appear to be a Footer class of any type in the documents. Now that I think about it, it would be nice to have a footer, especially if one wanted to sum up some columns...
If there isn't a builtin way to have one, one way to do it is to add a subview that mimics the footer and position the view at the bottom of the parent view or add it as a subview of the grid scrollview and position it in the viewable area and reposition it as the grid is scrolled.
In this post, I explained how I added a "Add New" button as a subview in the grid scrollview that scrolls along with the grid. You could probably use that and just replace the subview with the footer view and change the coordinates in the recalculateButtonPosition.
I admint it's a bit clunky but it might do the trick.
@ShinobiSquad: If it's not already a feature, it might be nice one to add.