记录一下UILabel加载富文本 iOS

时间：2023-03-09 23:14:41
记录一下UILabel加载富文本 iOS

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:]} range:NSMakeRange(, htmlString.length)];

//设置行间距

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

    [paragraphStyle setLineSpacing:];

 [htmlString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(, [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:]} range:NSMakeRange(, htmlString.length)];

    //设置行间距

    NSMutableParagraphStyle *paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];

    [paragraphStyle1 setLineSpacing:];

    [htmlString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(, [htmlString length])];

    CGSize textSize = [htmlString boundingRectWithSize:(CGSize){kScreenWidth - , CGFLOAT_MAX} options:NSStringDrawingUsesLineFragmentOrigin context:nil].size;

    return textSize.height ;

}

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