iOS开发 字符串添加行间距

+ (CGFloat)achiveWidthAttrString:(NSAttributedString *)attrString withHeight:(CGFloat)height {

  CGRect desRect = [attrString boundingRectWithSize:CGSizeMake(MAXFLOAT, height) options:NSStringDrawingUsesLineFragmentOrigin context:nil];

  return desRect.size.width;

}