private int[] sortOrdersIntoReorderedIndices(int childCount, List<Order> orders) {
        Collections.sort(orders);
        if (mOrderCache == null) {
            mOrderCache = new SparseIntArray(childCount);
        }
        mOrderCache.clear();
        int[] reorderedIndices = new int[childCount];
        int i = 0;
        for (Order order : orders) {
            reorderedIndices[i] = order.index;
            mOrderCache.append(i, order.order);
            i++;
        }
        return reorderedIndices;
    }
Create an array, which indicates the reordered indices that {@link LayoutParams#order}
attributes are taken into account.

@return @return an array which have the reordered indices
common/src/main/java/com/sxjs/common/widget/flexboxlayout/FlexboxLayout.java