根据文本内容自动计算文本高度

在开发过程中，经常需要根据文本内容自适应高度，并设置行间距，这是宽度一般给一个相对固定的宽度，

比如屏幕的宽度减去左右两边各15个像素的间距。下面是一个计算自适应高度的标题和内容的代码。sesameRemarkItemModel是一个字典类型，里面包含title和content字符串。

#define kCellHeightWithoutText25.0+15.0+12.0

#define kScreenWidth [UIScreen mainScreen].bounds.size.width

+ (CGFloat)heightForCellWithModel:(sesameRemarkItemModel *)model {

    if (!model) {

        return 44.0;

    }

    NSMutableDictionary *attr =[NSMutableDictionary dictionary];

    [attr safeSetObject:[UIFont systemFontOfSize:14] forKey:NSFontAttributeName];

    NSAttributedString *title =[[NSAttributedString alloc] initWithString:model.title attributes:attr];

    CGFloat titleHeight =[title boundingRectWithSize:CGSizeMake(kScreenWidth - 30, 2000) options:NSStringDrawingUsesLineFragmentOrigin context:nil].size.height;

    

    NSMutableDictionary *attr2 =[NSMutableDictionary dictionary];

    [attr2 safeSetObject:[UIFont systemFontOfSize:12] forKey:NSFontAttributeName];

    NSMutableParagraphStyle *style =[[NSMutableParagraphStyle alloc] init];

    style.lineSpacing = 5;

    [attr2 safeSetObject:style forKey:NSParagraphStyleAttributeName];

    NSAttributedString *content =[[NSAttributedString alloc] initWithString:model.content attributes:attr2];

    CGFloat contentHeight =[content boundingRectWithSize:CGSizeMake(kScreenWidth - 30, 2000) options:NSStringDrawingUsesLineFragmentOrigin context:nil].size.height;

    

    return kCellHeightWithoutText + titleHeight + contentHeight;

}