sizeWithFont 取消后

CGSize detailsLabelSize = [detailsLabel.text sizeWithFont:detailsLabel.font 
                                constrainedToSize:maxSize lineBreakMode:detailsLabel.lineBreakMode];

NSMutableParagraphStyle *para = [[NSMutableParagraphStyle alloc] init];
    para.lineBreakMode = detailsLabel.lineBreakMode;
    
    CGSize detailsLabelSize = [detailsLabel.text boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:detailsLabel.font,NSParagraphStyleAttributeName:para} context:nil].size;