从 NSAttributedString 中提取图像

Question

我正在做的是：

NSATTRIBUTE 字符串 = NSSTRING + UIMAGE 的；
NSDATA = NSATTRIBUTED 字符串；
我还可以将 nsdata 转换为 nsattributed 字符串
NSATTRIBUTED 字符串 = NSDATA:
然后从 NSAttributed 字符串中提取嵌套
NSSTRING = [NSATTRIBUTED STRING 字符串];

查询：

如何从 NSATTRIBUTED STRING 中获取图像；

UIIMAGE = 来自 NSATTRIBUTED 字符串；
ARRAYOFIMAGE = 来自 NSATTRIBUTED 字符串；

Answer 1

您必须枚举 NSAttributedString 以查找 NSTextAttachment。

NSMutableArray *imagesArray = [[NSMutableArray alloc] init];
[attributedString enumerateAttribute:NSAttachmentAttributeName
                             inRange:NSMakeRange(0, [attributedString length])
                             options:0
                          usingBlock:^(id value, NSRange range, BOOL *stop)
{
    if ([value isKindOfClass:[NSTextAttachment class]])
    {
    NSTextAttachment *attachment = (NSTextAttachment *)value;
    UIImage *image = nil;
    if ([attachment image])
        image = [attachment image];
    else
        image = [attachment imageForBounds:[attachment bounds]
                             textContainer:nil
                            characterIndex:range.location];

    if (image)
        [imagesArray addObject:image];
    }
}];

如您所见，有测试if ([attachment image])。那是因为看起来如果你创建了 NSTextAttachment 来放置 NSAttachmentAttributeName 它就会存在并且你的图像也会在那里。但是，如果您使用例如来自网络的图像并将其从 HTML 代码转换为 NSTextAttachment，则 [attachment image] 将为零并且您将无法获取图像.

您可以看到在此代码段中使用断点（设置真实图像 URL 和来自 bundle.xml 的真实图像名称）。 NSString *htmlString = @"http://anImageURL\">Blahttp://anOtherImageURL\"> 测试 retest";

NSError *error;
NSAttributedString *attributedStringFromHTML = [[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUTF8StringEncoding]
                                                                                options:@{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,
                                                                                          NSCharacterEncodingDocumentAttribute:@(NSUTF8StringEncoding)}
                                                                     documentAttributes:nil
                                                                                  error:&error];

NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
[textAttachment setImage:[UIImage imageNamed:@"anImageNameFromYourBundle"]];

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithAttributedString:attributedStringFromHTML];
[attributedString appendAttributedString:[NSAttributedString attributedStringWithAttachment:textAttachment]];

Answer 2

在 Swift 3 中：（相当于 macOS ）

func textViewDidChange(_ textView: UITextView) {

    // other code...

    let range = NSRange(location: 0, length: textView.attributedText.length)
    if (textView.textStorage.containsAttachments(in: range)) {
        let attrString = textView.attributedText
        var location = 0
        while location < range.length {
            var r = NSRange()
            let attrDictionary = attrString?.attributes(at: location, effectiveRange: &r)
            if attrDictionary != nil {
                // Swift.print(attrDictionary!)
                let attachment = attrDictionary![NSAttachmentAttributeName] as? NSTextAttachment
                if attachment != nil {
                    if attachment!.image != nil {
                        // your code to use attachment!.image as appropriate
                    }
                }
                location += r.length
            }
        }
    }
}

Answer 3

我将代码 Larme 转换为 swift 3

      var imagesArray = [Any]()

      textView.attributedText.enumerateAttribute(NSAttachmentAttributeName, in: NSRange(location: 0, length: textView.attributedText.length), options: [], using: {(value,range,stop) -> Void in
            if (value is NSTextAttachment) {
                let attachment: NSTextAttachment? = (value as? NSTextAttachment)
                var image: UIImage? = nil

                if ((attachment?.image) != nil) {
                    image = attachment?.image 
                } else {
                    image = attachment?.image(forBounds: (attachment?.bounds)!, textContainer: nil, characterIndex: range.location)
                }

                if image != nil {
                  imagesArray.append(image)
                }
            }
        })

从 NSAttributedString 中提取图像

Extract UIImage from NSAttributed String

ios

uiimage

nsattributedstring