計(jì)算YYLabel內(nèi)容富文本(帶行間距)attributeStr的高度，假設(shè)行間距間距是5，走的彎路：

一、根據(jù)內(nèi)容求高度

/// 帶有行間距求高度 假如是行間距是5
- (CGRect)boundsWithFont:(UIFont *)font text:(NSString *)text needWidth:(CGFloat)needWidth lineSpacing:(CGFloat )lineSpacing
{ 
    NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:text];
    // 樣式
    NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
    style.lineSpacing = lineSpacing; // 行間距
    style.lineBreakMode = NSLineBreakByWordWrapping;
   // 樣式
    [attributeString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, text.length)];
   // 文字大小
    [attributeString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:textFontValue15] range:NSMakeRange(0, text.length)];
    
    NSStringDrawingOptions options = NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading;
    CGRect rect = [attributeString boundingRectWithSize:CGSizeMake(needWidth, CGFLOAT_MAX) options:options context:nil];
    
    return rect;
    
}

二、 YYLabel賦值NSString->NSAttributedString（帶行間距）

/// 設(shè)置行間距的NSAttributedString賦值給YYLabel
- (NSAttributedString *)matchesAttributedString:(NSString *)str{
    NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc] initWithString:str];

    // 間距
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:5.0]; // 行間距假如是5
    paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;
    [attrStr addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [str length])];
    
    [attrStr addAttribute:NSForegroundColorAttributeName value:UIColorFromHEX(0x242831) range:NSMakeRange(0, attrStr.length)];
    [attrStr addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:textFontValue15] range:NSMakeRange(0, attrStr.length)];

   
    return attrStr;
}

當(dāng)文本比較多的時候展示出的空白比較多，根據(jù)觀察是展示的行間距小于5.0，所以整體偏中聚集，上下留白較多。但是對于UILabel是沒有問題的。

三、3.1 對于YYLabel正確的做法是如下所示：

     // 計(jì)算文本尺寸YYTextLayout
     CGSize maxSize = CGSizeMake(fixWidth, MAXFLOAT);
     
     YYTextLayout *layout = [YYTextLayout layoutWithContainerSize:maxSize text:self.contentLbl.attributedText];
     self.contentLbl.textLayout = layout;
     CGFloat introHeight = layout.textBoundingSize.height;
        
     self.contentLbl.width = maxSize.width;
     // 記錄真正的正確高度
     contentH = introHeight; 

3.2 不借助控件求高度：

CGSize maxSize = CGSizeMake(fixWidth, MAXFLOAT);
        
//計(jì)算文本尺寸
YYTextLayout *layout = [YYTextLayout layoutWithContainerSize:maxSize text:[self matchesAttributedString:@"普通文本內(nèi)容"]];
CGFloat introHeight = layout.textBoundingSize.height;
contentH = introHeight; // 高度

注：matchesAttributedString:自定義的方法，NSString->NSAttributedString見上文