private int findMotionHeader(float y) {
        if (mStickiedHeader != null && y <= mHeaderBottomPosition) {
            return MATCHED_STICKIED_HEADER;
        }

        int vi = 0;
        for (int i = getFirstVisiblePosition(); i <= getLastVisiblePosition();) {
            long id = getItemIdAtPosition(i);
            if (id == StickyGridHeadersBaseAdapterWrapper.ID_HEADER) {
                View headerWrapper = getChildAt(vi);

                int bottom = headerWrapper.getBottom();
                int top = headerWrapper.getTop();
                if (y <= bottom && y >= top) {
                    return vi;
                }
            }
            i += mNumMeasuredColumns;
            vi += mNumMeasuredColumns;
        }

        return NO_MATCHED_HEADER;
    }
If set to true, headers will ignore horizontal padding.

@param b if true, horizontal padding is ignored by headers
Library/src/com/tonicartos/widget/stickygridheaders/StickyGridHeadersGridView.java