private boolean allFlexLinesAreDummyBefore(int flexLineIndex) {
        for (int i = 0; i < flexLineIndex; i++) {
            if (mFlexLines.get(i).getItemCountNotGone() > 0) {
                return false;
            }
        }
        return true;
    }
Check if a divider is needed before the flex line whose index is passed as an argument.

@param flexLineIndex the index of the flex line to be checked
@return {@code true} if a divider is needed, {@code false} otherwise
common/src/main/java/com/sxjs/common/widget/flexboxlayout/FlexboxLayout.java