public int setFooterView(View header, int index, int orientation) {
        if (mFooterLayout == null || mFooterLayout.getChildCount() <= index) {
            return addFooterView(header, index, orientation);
        } else {
            mFooterLayout.removeViewAt(index);
            mFooterLayout.addView(header, index);
            return index;
        }
    }
Add footer view to mFooterLayout and set footer view position in mFooterLayout.
When index = -1 or index >= child count in mFooterLayout,
the effect of this method is the same as that of {@link #addFooterView(View)}.

@param footer
@param index  the position in mFooterLayout of this footer.
              When index = -1 or index >= child count in mFooterLayout,
              the effect of this method is the same as that of {@link #addFooterView(View)}.
common/src/main/java/com/sxjs/common/base/baseadapter/BaseQuickAdapter.java