protected void updateCount() {
        mCount = 0;
        int numHeaders = mDelegate.getNumHeaders();
        if (numHeaders == 0) {
            mCount = mDelegate.getCount();
            mCounted = true;
            return;
        }

        for (int i = 0; i < numHeaders; i++) {
            mCount += mDelegate.getCountForHeader(i) + mNumColumns;
        }
        mCounted = true;
    }
Counts the number of items that would be need to fill out the last row in
the group of items with the given header.

@param header Header set of items are grouped by.
@return The count of unfilled spaces in the last row.
Library/src/com/tonicartos/widget/stickygridheaders/StickyGridHeadersBaseAdapterWrapper.java