Extension for UITapGesture that contains a function to detect range of particular text in UILabel's text.

UITapGesture.swift

extension UITapGestureRecognizer {
    
    func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
        // Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: CGSize.zero)
        let textStorage = NSTextStorage(attributedString: label.attributedText!)
        
        // Configure layoutManager and textStorage
        layoutManager.addTextContainer(textContainer)
        textStorage.addLayoutManager(layoutManager)
        
        // Configure textContainer
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines
        let labelSize = label.bounds.size
        textContainer.size = labelSize
        
        // Find the tapped character location and compare it to the specified range
        let locationOfTouchInLabel = self.location(in: label)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
                                          y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x,
                                                     y: locationOfTouchInLabel.y - textContainerOffset.y);
        var indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        indexOfCharacter = indexOfCharacter + 4
        return NSLocationInRange(indexOfCharacter, targetRange)
    }
    
}

thanks this helping me

Thank you! Super helpful

might it be calculating indexOfCharacter wrongly?
I'm clicking the very end of the underlined text "User agreement":
textRange NSRange location=42, length=10
indexOfCharacter Int 56

Yes its calculating wrong, please check the updated code here

might it be calculating indexOfCharacter wrongly?
I'm clicking the very end of the underlined text "User agreement":
textRange NSRange location=42, length=10
indexOfCharacter Int 56

so you have basically added 4 to indexOfCharacter? I don't think it's the right solution.

Yes its not but for the time being its a quick fix. Will review it later on and put a right solution.

…

On Wed, 13 May 2020, 5:35 pm Canberk Ozcelik, ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ so you have basically added 4 to indexOfCharacter? I don't think it's the right solution. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/2d00d7de485b8f261e010fff333cba0f#gistcomment-3302527>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACFA4H4YKTOHBT4W7EAYWETRRKEH5ANCNFSM4JKT2DHA> .

It's reasonable 👍 just for the ones having multiline text with 4-5 text links in it, do not choose this approach

Just delete (indexOfCharacter = indexOfCharacter + 4 ) this line of code :)

indexOfCharater is a let variable, how is it being changed in the next line?

As pointed out by @canberkozcelik this approach does not work for multi line text.

After digging a bit I found out that multi line works only if the label's lineBreakMode is set to byWordWrapping. This way the textBoundingBox's height is correctly calculated.

https://stackoverflow.com/questions/36043006/tap-on-a-part-of-text-of-uilabel

Still faced issue in the solution while tapping.

Check Here's the RIGHT SOLUTION.

`func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {

    // Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
    let layoutManager = NSLayoutManager()
    let textContainer = NSTextContainer(size: CGSize.zero)
    let textStorage = NSTextStorage(attributedString: label.attributedText!)
   
    // Configure layoutManager and textStorage
    layoutManager.addTextContainer(textContainer)
    textStorage.addLayoutManager(layoutManager)
    
    // Configure textContainer
    textContainer.lineFragmentPadding = 0.0
    textContainer.lineBreakMode = NSLineBreakMode.byWordWrapping
    textContainer.maximumNumberOfLines = label.numberOfLines
    let labelSize = label.bounds.size
    textContainer.size = labelSize
    
    // Find the tapped character location and compare it to the specified range
    let locationOfTouchInLabel = self.location(in: label)
    let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x , y: locationOfTouchInLabel.y)
    let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
    
    return NSLocationInRange(indexOfCharacter, targetRange)
}`

@geek-Shayan Thanks for the simplified code.
I am still facing some issue problem where the characterIndex is calculated incorrectly as the Number of lines increases.
I found UILabel's attributed text's default size is slightly larger than UITextView's Attributed Text (which uses layoutManager and textStorage inside it).

For now the working solution is giving the entire attributed string constant font size or scaledValue attributes: [.font: UIFont.systemFont(ofSize: UIFontMetrics.default.scaledValue(for: xSize))]

Tag me if anyone found proper solution