private int getSumOfCrossSize() {
        int sum = 0;
        for (int i = 0, size = mFlexLines.size(); i < size; i++) {
            FlexLine flexLine = mFlexLines.get(i);

            // Judge if the beginning or middle dividers are required
            if (hasDividerBeforeFlexLine(i)) {
                if (isMainAxisDirectionHorizontal(mFlexDirection)) {
                    sum += mDividerHorizontalHeight;
                } else {
                    sum += mDividerVerticalWidth;
                }
            }

            // Judge if the end divider is required
            if (hasEndDividerAfterFlexLine(i)) {
                if (isMainAxisDirectionHorizontal(mFlexDirection)) {
                    sum += mDividerHorizontalHeight;
                } else {
                    sum += mDividerVerticalWidth;
                }
            }
            sum += flexLine.mCrossSize;
        }
        return sum;
    }
Retrieve the sum of the cross sizes of all flex lines including divider lengths.

@return the sum of the cross sizes
common/src/main/java/com/sxjs/common/widget/flexboxlayout/FlexboxLayout.java