private int getLargestMainSize() {
        int largestSize = Integer.MIN_VALUE;
        for (FlexLine flexLine : mFlexLines) {
            largestSize = Math.max(largestSize, flexLine.mMainSize);
        }
        return largestSize;
    }
Retrieve the largest main size of all flex lines.

@return the largest main size
common/src/main/java/com/sxjs/common/widget/flexboxlayout/FlexboxLayout.java