Extract UIImage from NSAttributed String

问题

What I am doing is:

NSATTRIBUTE STRING = NSSTRING + UIIMAGE\'s;
NSDATA = NSATTRIBUTED STRING;
ALSO I am able to convert nsdata to nsattributed string
NSATTRIBUTED STRING = NSDATA:
And then extracting nesting from NSAttributed string
NSSTRING = [NSATTRIBUTED STRING string];

Query:

How can i get IMAGES from NSATTRIBUTED STRING;

UIIMAGE = from NSATTRIBUTED STRING;
ARRAYOFIMAGE = from NSATTRIBUTED STRING;

回答1:

You have to enumerate the NSAttributedString looking for NSTextAttachments.

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];
    }
}];

As you can see, there is the test if ([attachment image]). That's because it seems that if you created the NSTextAttachment to put with NSAttachmentAttributeName it will exist and your image will be there. But if you use for example an image from the web and convert it as a NSTextAttachment from a HTML code, then [attachment image] will be nil and you won't be able to get the image.

You can see using breakpoints with this snippet (with setting real image URL and an real image name from bundle. NSString *htmlString = @"http://anImageURL\">Blahttp://anOtherImageURL\"> Test 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]];

回答2:

In Swift 3: (with macOS equivalent here)

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
            }
        }
    }
}

回答3:

I converted the code Larme to 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)
                }
            }
        })

来源：https://stackoverflow.com/questions/29152660/extract-uiimage-from-nsattributed-string

标签

ios

uiimage

nsattributedstring