一般情况下我们都习惯用webview加载富文本。但是webview比较消耗内存。然后发现其实本身可以用uilabel加载，性能还不错就记录下~~
核心方法下面两个
-(NSMutableAttributedString *)setAttributedString:(NSString *)str { //如果有换行，把\n替换成<br/> //如果有需要把换行加上 str = [str stringByReplacingOccurrencesOfString:@"\n" withString:@"<br/>"]; //设置HTML图片的宽度 str = [NSString stringWithFormat:@"<head><style>img{width:%f !important;height:auto}</style></head>%@",[UIScreen mainScreen].bounds.size.width,str]; NSMutableAttributedString *htmlString =[[NSMutableAttributedString alloc] initWithData:[str dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute:[NSNumber numberWithInt:NSUTF8StringEncoding]} documentAttributes:NULL error:nil]; //设置富文本字的大小 [htmlString addAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:16]} range:NSMakeRange(0, htmlString.length)]; //设置行间距 NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init]; [paragraphStyle setLineSpacing:5]; [htmlString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [htmlString length])]; return htmlString; } //计算html字符串高度 -(CGFloat )getHTMLHeightByStr:(NSString *)str { str = [str stringByReplacingOccurrencesOfString:@"\n" withString:@"<br/>"]; str = [NSString stringWithFormat:@"<head><style>img{width:%f !important;height:auto}</style></head>%@",[UIScreen mainScreen].bounds.size.width,str]; NSMutableAttributedString *htmlString =[[NSMutableAttributedString alloc] initWithData:[str dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute:[NSNumber numberWithInt:NSUTF8StringEncoding]} documentAttributes:NULL error:nil]; [htmlString addAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:16]} range:NSMakeRange(0, htmlString.length)]; //设置行间距 NSMutableParagraphStyle *paragraphStyle1 = [[NSMutableParagraphStyle alloc] init]; [paragraphStyle1 setLineSpacing:5]; [htmlString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [htmlString length])]; CGSize textSize = [htmlString boundingRectWithSize:(CGSize){kScreenWidth - 30, CGFLOAT_MAX} options:NSStringDrawingUsesLineFragmentOrigin context:nil].size; return textSize.height ; }
原文：https://www.cnblogs.com/110-913-1025/p/11946987.html