How to make UITextView detect hashtags?

Question

I know that the UITextView default can detect URL, but how can i make it detect hashtags(#)?

It doesn't needs to detect hashtags while typing, but then viewDidLoad the text is set in the UITextView, so i want to detect hashtags as a color or something.

I have been using ActiveLabel, but that is only for UILabel, and i need the scroll function that the UITextView has.

Answer 1

One option would be to use an NSAttributedString, something like this...

func convertHashtags(text:String) -> NSAttributedString {
    let attrString = NSMutableAttributedString(string: text)
    attrString.beginEditing()
    // match all hashtags
    do {
        // Find all the hashtags in our string
        let regex = try NSRegularExpression(pattern: "(?:\\s|^)(#(?:[a-zA-Z].*?|\\d+[a-zA-Z]+.*?))\\b", options: NSRegularExpressionOptions.AnchorsMatchLines)
        let results = regex.matchesInString(text,
            options: NSMatchingOptions.WithoutAnchoringBounds, range: NSMakeRange(0, text.characters.count))
        let array = results.map { (text as NSString).substringWithRange($0.range) }
        for hashtag in array {
            // get range of the hashtag in the main string
            let range = (attrString.string as NSString).rangeOfString(hashtag)
            // add a colour to the hashtag
            attrString.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor() , range: range)
        }
        attrString.endEditing()
    }
    catch {
        attrString.endEditing()
    }
    return attrString
}

Then assign your attributedText like this...

let myText = "some text with a #hashtag in side of it #itsnoteasy"
self.textView.attributedText = convertHashtags(myText)

Answer 2

This should work for you

1. Create a new swift file with any name(UITextViewHashtagExtension.swift)

2. Insert this code below:

   import UIKit
   
   extension UITextView {
   
   func resolveHashTags(){
   
       // turn string in to NSString
       let nsText:NSString = self.text
   
       // this needs to be an array of NSString.  String does not work.
       let words:[NSString] = nsText.componentsSeparatedByString(" ")
   
       // you can't set the font size in the storyboard anymore, since it gets overridden here.
       let attrs = [
           NSFontAttributeName : UIFont.systemFontOfSize(17.0)
       ]
   
       // you can staple URLs onto attributed strings
       let attrString = NSMutableAttributedString(string: nsText as String, attributes:attrs)
   
       // tag each word if it has a hashtag
       for word in words {
   
           // found a word that is prepended by a hashtag!
           // homework for you: implement @mentions here too.
           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.
               let matchRange:NSRange = nsText.rangeOfString(word as String)
   
               // convert the word from NSString to String
               // this allows us to call "dropFirst" to remove the hashtag
               var stringifiedWord:String = word as String
   
               // drop the hashtag
               stringifiedWord = String(stringifiedWord.characters.dropFirst())
   
               // check to see if the hashtag has numbers.
               // ribl is "#1" shouldn't be considered a hashtag.
               let digits = NSCharacterSet.decimalDigitCharacterSet()
   
               if let numbersExist = stringifiedWord.rangeOfCharacterFromSet(digits) {
                   // 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(NSLinkAttributeName, value: "hash:\(stringifiedWord)", range: matchRange)
               }
   
           }
       }
   
       // we're used to textView.text
       // but here we use textView.attributedText
       // again, this will also wipe out any fonts and colors from the storyboard,
       // so remember to re-add them in the attrs dictionary above
       self.attributedText = attrString
   }
   
   }
   

---

To use this you can do something like this:

self.textView.text = "This is an #example test"
self.textView.resolveHashTags()

---

Updated for Swift 4.0:

extension UITextView {

    func resolveHashTags() {

        // turn string in to NSString
        let nsText = NSString(string: self.text)

        // this needs to be an array of NSString.  String does not work.
        let words = nsText.components(separatedBy: CharacterSet(charactersIn: "#ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_").inverted)

        // you can staple URLs onto attributed strings
        let attrString = NSMutableAttributedString()
        attrString.setAttributedString(self.attributedText)

        // tag each word if it has a hashtag
        for word in words {
            if word.count < 3 {
                continue
            }

            // found a word that is prepended by a hashtag!
            // homework for you: implement @mentions here too.
            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.
                let matchRange:NSRange = nsText.range(of: word as String)

                // 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(NSAttributedStringKey.link, value: "hash:\(stringifiedWord)", range: matchRange)
                }

            }
        }

        // we're used to textView.text
        // but here we use textView.attributedText
        // again, this will also wipe out any fonts and colors from the storyboard,
        // so remember to re-add them in the attrs dictionary above
        self.attributedText = attrString
    }
}

Answer 3

For Swift 3 +

 extension UITextView {
        
        func convertHashtags(text:String) -> NSAttributedString {
            
            let attr = [
                NSFontAttributeName : UIFont.systemFont(ofSize: 17.0),
                NSForegroundColorAttributeName : clr_golden,    
                NSLinkAttributeName : "https://Laitkor.com"
             ] as [String : Any]

        
        let attrString = NSMutableAttributedString(string: text)
        attrString.beginEditing()
        // match all hashtags
        do {
            // Find all the hashtags in our string
            let regex = try NSRegularExpression(pattern: "(?:\\s|^)(#(?:[a-zA-Z].*?|\\d+[a-zA-Z]+.*?))\\b", options: NSRegularExpression.Options.anchorsMatchLines)
            let results = regex.matches(in: text,
                                                options: NSRegularExpression.MatchingOptions.withoutAnchoringBounds, range: NSMakeRange(0, text.characters.count))
            let array = results.map { (text as NSString).substring(with: $0.range) }
            for hashtag in array {
                // get range of the hashtag in the main string
                let range = (attrString.string as NSString).range(of: hashtag)
                // add a colour to the hashtag
                //attrString.addAttribute(NSForegroundColorAttributeName, value: clr_golden , range: range)
                attrString.addAttributes(attr, range: range)
            }
            attrString.endEditing()
        }
        catch {
            attrString.endEditing()
        }
        return attrString
    }
}

Add UITextViewDelegate in your class and Use like this

 self.tv_yourTextView.delegate = self
 self.tv_yourTextView.attributedText = tv_yourTextView.convertHashtags(text: "This is an #museer test")

delegate funtion

func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange) -> Bool {
    print("hastag Selected!")
    return true
}

-> Modified @Wez Answer