Extract UIImage from NSAttributed String

Question

What I am doing is:

1. NSATTRIBUTE STRING = NSSTRING + UIIMAGE's;
2. NSDATA = NSATTRIBUTED STRING;
3. ALSO I am able to convert nsdata to nsattributed string
4. NSATTRIBUTED STRING = NSDATA:
5. And then extracting nesting from NSAttributed string
6. NSSTRING = [NSATTRIBUTED STRING string];

Query:

How can i get IMAGES from NSATTRIBUTED STRING;

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

Answer 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]];

Answer 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
            }
        }
    }
}