Keep hyperlink to specific word in UITextView using attributedString - ios

Question

I'm trying to implement an editor that can handle hashtag while typing.
extension UITextView {
func resolveHashTags() {
if self.text.isEmpty {
let emptyString = NSMutableAttributedString(string: " ", attributes: [NSAttributedString.Key.foregroundColor: UIColor.black,
NSAttributedString.Key.font: self.font!])
self.attributedText = emptyString
self.textColor = .black
self.text = ""
return
}
let cursorRange = selectedRange
let nsText = NSString(string: self.text)
let words = nsText.components(separatedBy: CharacterSet(charactersIn: "##ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_").inverted).filter({!$0.isEmpty})
self.textColor = .black
let attrString = NSMutableAttributedString()
attrString.setAttributedString(self.attributedText)
attrString.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.black], range: nsText.range(of: self.text))
var anchor: Int = 0
for word in words {
// found a word that is prepended by a hashtag!
// homework for you: implement #mentions here too.
let matchRange:NSRange = nsText.range(of: word as String, range: NSRange(location: anchor, length: nsText.length - anchor))
anchor = matchRange.location + matchRange.length
if word.hasPrefix("#") {
// a range is the character position, followed by how many characters are in the word.
// we need this because we staple the "href" to this range.
// drop the hashtag
let stringifiedWord = word.dropFirst()
if let firstChar = stringifiedWord.unicodeScalars.first, NSCharacterSet.decimalDigits.contains(firstChar) {
// hashtag contains a number, like "#1"
// so don't make it clickable
} else {
// set a link for when the user clicks on this word.
// it's not enough to use the word "hash", but you need the url scheme syntax "hash://"
// note: since it's a URL now, the color is set to the project's tint color
attrString.addAttribute(NSAttributedString.Key.link, value: "hash:\(stringifiedWord)", range: matchRange)
}
} else if !word.hasPrefix("#") {
}
}
self.attributedText = attrString
self.selectedRange = cursorRange
}
}
So this is the extension I'm using to create a hyperlink in UITextView. Called in func textViewDidChange(_ textView: UITextView)
So while typing if any word starts with #. It'll turn in hyperlinks and will change color to blue. After typing the intended word if you press space it goes back to black text. This is expected behavior.
But if you clear text and move your course back to hashtag word like this
it keeps extending hyperlink to the next word too.
any solution to keep hyperlinks to that word only. Anything typed after hashtag should be normal text

Answer 1

I finally figured it out.
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
var shouldReturn = true
let selectedRange = textView.selectedRange
let attributedText = NSMutableAttributedString(attributedString: textView.attributedText)
if !text.isEmpty && text != " " {
var userAttributes = [(NSAttributedString.Key, Any, NSRange)]()
attributedText.enumerateAttribute(.link, in: _NSRange(location: 0, length: textView.text.count), options: .longestEffectiveRangeNotRequired) { (value, range, stop) in
if let url = value as? String, url.hasPrefix("user:") {
userAttributes.append((.link, value!, range))
}
}
if let userLink = userAttributes.first(where: {$0.2.contains(range.location - 1)}) {
attributedText.replaceCharacters(in: range, with: NSAttributedString(string: text, attributes: [NSAttributedString.Key.link : userLink.1, NSAttributedString.Key.font : textView.font as Any]))
textView.attributedText = attributedText
shouldReturn = false
} else {
attributedText.replaceCharacters(in: range, with: NSAttributedString(string: text, attributes: [NSAttributedString.Key.font : textView.font as Any]))
textView.attributedText = attributedText
textDidChange?(textView)
shouldReturn = false
}
textView.selectedRange = _NSRange(location: selectedRange.location + text.count, length: 0)
textViewDidChange(textView)
}
return shouldReturn
}
This way I have the control to update the link in between the word and it doesn't extend afterward to a new word.