記錄一下UILabel加載富文本 iOS

時間 2020-06-18

標籤記錄一下 uilabel 加載文本 ios 欄目 iOS 简体版

原文原文鏈接

通常狀況下咱們都習慣用webview加載富文本。可是webview比較消耗內存。而後發現其實自己能夠用uilabel加載，性能還不錯就記錄下~~html

核心方法下面兩個web

-(NSMutableAttributedString *)setAttributedString:(NSString *)str
{
//若是有換行，把\n替換成<br/>
//若是有須要把換行加上
 str = [str stringByReplacingOccurrencesOfString:@"\n" withString:@"<br/>"];
//設置HTML圖片的寬度
 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];
//設置富文本字的大小
 [htmlString addAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:16]} range:NSMakeRange(0, htmlString.length)];
//設置行間距
 NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:5];
 [htmlString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [htmlString length])];
    return htmlString;
}

//計算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)];
    //設置行間距
    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 ;
}

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