DTCoreText学习

DTCoreText主要用于富文本

倒入头文件
#import <DTCoreText/DTCoreText.h>
创建
@property (nonatomic, strong) DTAttributedLabel *contentLabel;

    [_viewContent addSubview:({
        _contentLabel = [DTAttributedLabel new];

        _contentLabel.numberOfLines = 0;
        _contentLabel.delegate =self;
        
        _contentLabel;
    })];
    
协议
DTAttributedTextContentViewDelegate,DTLazyImageViewDelegate

代理详情

#pragma mark - DTAttributedTextContentViewDelegate
- (UIView *)attributedTextContentView:(DTAttributedTextContentView *)attributedTextContentView viewForAttachment:(DTTextAttachment *)attachment frame:(CGRect)frame{
    //如果是图片，获取图片并显示，这里第一次得到的frame的宽高都为0，需要通过imageView代理计算，重新加载
    if([attachment isKindOfClass:[DTImageTextAttachment class]])
    {
        DTLazyImageView *imageView = [[DTLazyImageView alloc] initWithFrame:frame];
        imageView.url = attachment.contentURL;
        imageView.delegate = self;
        imageView.image = [(DTImageTextAttachment *)attachment image];

        return imageView;
    }
    return nil;
}

#pragma mark - DTLazyImageViewDelegate
MARK: - 根据获取图片size重新加载
- (void)lazyImageView:(DTLazyImageView *)lazyImageView didChangeImageSize:(CGSize)size
{
    CGFloat width = SCREEN_WIDTH-kWidth(40);//自己设定的宽
    CGSize imageSize = size;
    if (size.width > width) {
        CGFloat height = width * (size.height/size.width);
        imageSize = CGSizeMake(width, height);
    }

    NSURL *url = lazyImageView.url;
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"contentURL == %@", url];
    BOOL didUpdate = NO;

    for (DTTextAttachment *oneAttachment in [self.contentLabel.layoutFrame textAttachmentsWithPredicate:pred]) {
        if (CGSizeEqualToSize(oneAttachment.displaySize, CGSizeZero)) {
            oneAttachment.displaySize = imageSize;
            [self configNoSizeImageView:url.absoluteString size:imageSize];
            didUpdate = YES;
        }
    }

    if (didUpdate) {
      CGRect maxRect =  CGRectMake(kWidth(20), kWidth(20), SCREEN_WIDTH-kWidth(40), CGFLOAT_HEIGHT_UNKNOWN);
      CGSize textSize = [self getAttributedTextHeightHtml:self.viewModel.eventsItem.content with_viewMaxRect:maxRect];
       self.contentLabel.attributedString = [self getAttributedStringWithHtml:self.viewModel.eventsItem.content];
        [self.contentLabel mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(self.detailLabel.mas_bottom).offset = kHeigh(16);
            make.leading.offset = kWidth(20);
            make.trailing.offset = -kWidth(20);
            make.height.mas_equalTo(textSize.height);
        }];
    }
}
#pragma mark - private Methods
//使用得到的新图片尺寸，更新HtmlString字符串
- (void)configNoSizeImageView:(NSString *)url size:(CGSize)size{
    //_viewMaxRect是预设的最大Frame
    CGRect maxRect =  CGRectMake(kWidth(20), kWidth(20), SCREEN_WIDTH-kWidth(40), CGFLOAT_HEIGHT_UNKNOWN);
    CGFloat imgSizeScale = size.height/size.width;
    CGFloat widthPx = maxRect.size.width;
    CGFloat heightPx = widthPx * imgSizeScale;
    NSString *imageInfo = [NSString stringWithFormat:@"src=\"%@\"",url];
    NSString *sizeString = [NSString stringWithFormat:@"style=\"width:%.fpx; height:%.fpx;\"",widthPx,heightPx];
    NSString *newImageInfo = [NSString stringWithFormat:@"src=\"%@\"%@",url,sizeString];
    if ([self.viewModel.eventsItem.content containsString:imageInfo]) {
        NSString *newHtml = [self.viewModel.eventsItem.content stringByReplacingOccurrencesOfString:imageInfo withString:newImageInfo];
        self.viewModel.eventsItem.content = newHtml;
    }
}

//使用HtmlString,和预设的Frame，计算富文本视图自适应后的高度
- (CGSize)getAttributedTextHeightHtml:(NSString *)htmlString with_viewMaxRect:(CGRect)_viewMaxRect{
    //获取富文本
    NSAttributedString *attributedString =  [self getAttributedStringWithHtml:htmlString];
    //获取布局器
    DTCoreTextLayouter *layouter = [[DTCoreTextLayouter alloc] initWithAttributedString:attributedString];
    NSRange entireString = NSMakeRange(0, [attributedString length]);
    //获取Frame
    DTCoreTextLayoutFrame *layoutFrame = [layouter layoutFrameWithRect:_viewMaxRect range:entireString];
    //得到大小
    CGSize sizeNeeded = [layoutFrame frame].size;
    return sizeNeeded;
}

//Html->富文本NSAttributedString
- (NSAttributedString *)getAttributedStringWithHtml:(NSString *)htmlString{
    //获取富文本
    NSData *data = [htmlString dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithHTMLData:data documentAttributes:NULL];

    NSRange range = NSMakeRange(0, attributedString.length);
    if (range.length>0) {
        NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
        [paragraphStyle setLineSpacing:0];//调整行间距
        paragraphStyle.maximumLineHeight = kScale(22);
        paragraphStyle.minimumLineHeight = kScale(22);
        [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:range];
        [attributedString addAttribute:NSForegroundColorAttributeName value:XAsset.color_joyEventsDetailContent range:range];
        [attributedString addAttribute:NSFontAttributeName value:XAsset.font_joyEventsDetailContent range:range];
    }

    return attributedString;
}