@Override
    public void addView(View child, int index, ViewGroup.LayoutParams params) {
        // Create an array for the reordered indices before the View is added in the parent
        // ViewGroup since otherwise reordered indices won't be in effect before the
        // FlexboxLayout's onMeasure is called.
        // Because requestLayout is requested in the super.addView method.
        mReorderedIndices = createReorderedIndices(child, index, params);
        super.addView(child, index, params);
    }
Returns a View, which is reordered by taking {@link LayoutParams#order} parameters
into account.

@param index the index of the view
@return the reordered view, which {@link LayoutParams@order} is taken into account.
If the index is negative or out of bounds of the number of contained views,
returns {@code null}.
common/src/main/java/com/sxjs/common/widget/flexboxlayout/FlexboxLayout.java