How to underline a UILabel in swift?

Question

How to underline a UILabel in Swift? I searched the Objective-C ones but couldn't quite get them to work in Swift.

Sour

NSAttributedString? – Explicable

whats with the dislikes? there is an obvious confusion here with the attibutes looking like method calls in objc – Sour

here You Can get the easy way #28268560 – Padraig

here are the easy way [#28268560 – Padraig

Better solution algorithm with better solution you can look my answer #28053834 – Ette

Answer 1

You can do this using NSAttributedString

Example:

let underlineAttribute = [NSAttributedString.Key.underlineStyle: NSUnderlineStyle.thick.rawValue]
let underlineAttributedString = NSAttributedString(string: "StringWithUnderLine", attributes: underlineAttribute)
myLabel.attributedText = underlineAttributedString

EDIT

To have the same attributes for all texts of one UILabel, I suggest you to subclass UILabel and overriding text, like that:

Swift 5

Same as Swift 4.2 but: You should prefer the Swift initializer NSRange over the old NSMakeRange, you can shorten to .underlineStyle and linebreaks improve readibility for long method calls.

class UnderlinedLabel: UILabel {

override var text: String? {
    didSet {
        guard let text = text else { return }
        let textRange = NSRange(location: 0, length: text.count)
        let attributedText = NSMutableAttributedString(string: text)
        attributedText.addAttribute(.underlineStyle,
                                    value: NSUnderlineStyle.single.rawValue,
                                    range: textRange)
        // Add other attributes if needed
        self.attributedText = attributedText
        }
    }
}

Swift 4.2

class UnderlinedLabel: UILabel {

override var text: String? {
    didSet {
        guard let text = text else { return }
        let textRange = NSMakeRange(0, text.count)
        let attributedText = NSMutableAttributedString(string: text)
        attributedText.addAttribute(NSAttributedString.Key.underlineStyle , value: NSUnderlineStyle.single.rawValue, range: textRange)
        // Add other attributes if needed
        self.attributedText = attributedText
        }
    }
}

Swift 3.0

class UnderlinedLabel: UILabel {
    
    override var text: String? {
        didSet {
            guard let text = text else { return }
            let textRange = NSMakeRange(0, text.characters.count)
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName , value: NSUnderlineStyle.styleSingle.rawValue, range: textRange)
            // Add other attributes if needed
            self.attributedText = attributedText
        }
    }
}

And you put your text like this :

@IBOutlet weak var label: UnderlinedLabel!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        label.text = "StringWithUnderLine"
    }

OLD:

Swift (2.0 to 2.3):

class UnderlinedLabel: UILabel {
    
    override var text: String? {
        didSet {
            guard let text = text else { return }
            let textRange = NSMakeRange(0, text.characters.count)
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName, value:NSUnderlineStyle.StyleSingle.rawValue, range: textRange)
            // Add other attributes if needed
            
            self.attributedText = attributedText
        }
    }
}

Swift 1.2:

class UnderlinedLabel: UILabel {
    
    override var text: String! {
        didSet {
            let textRange = NSMakeRange(0, count(text))
            let attributedText = NSMutableAttributedString(string: text)
            attributedText.addAttribute(NSUnderlineStyleAttributeName, value:NSUnderlineStyle.StyleSingle.rawValue, range: textRange)
            // Add other attributes if needed
            
            self.attributedText = attributedText
        }
    }
}

Mccollum

What would be the best way to de-underline? – Quartered

I've been wondering for a long time: why do we have to use rawValue otherwise it crashes? – Pantsuit

You should pass UTF16 count instead of the character count when creating your textRange NSRange – Tedium

I've changed this solution to add a underlline on initialize, this way we can use it easily with storyboards required init?(coder: NSCoder) { super.init(coder: coder) self.addUnderline() // your code } – Revitalize

Better solution algorithm with better solution you can look my answer #28053834 – Ette

Answer 2

Swift 5 & 4.2 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
    [.underlineStyle: NSUnderlineStyle.single.rawValue])

Swift 4 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
    [.underlineStyle: NSUnderlineStyle.styleSingle.rawValue])

Swift 3 one liner:

label.attributedText = NSAttributedString(string: "Text", attributes:
      [NSUnderlineStyleAttributeName: NSUnderlineStyle.styleSingle.rawValue])

Tartlet

NSUnderlineStyle.styleSingle.rawValue has been renamed to NSUnderlineStyle.single.rawValue in swift 4.2 – Belleslettres

How do I de-underline? – Quartered

@N.Der Set again a normal text to label – Goto

Answer 3

Swift 5:

1- Create a String extension to get attributedText

extension String {

    var underLined: NSAttributedString {
        NSMutableAttributedString(string: self, attributes: [.underlineStyle: NSUnderlineStyle.single.rawValue])
    }

}

2- Use it

On buttons:

<#YourButton#>.setAttributedTitle(<#YourButtonTitle#>.underLined, for: .normal)

On Labels:

<#YourLabel#>.attributedText = <#YourLabelTitle#>.underLined

Or Stoyboard version

Penn

The above extension worked out for me, thanks. – Eponym

Answer 4

If you are looking for a way to do this without inheritance:

Swift 5

extension UILabel {
    func underline() {
        if let textString = self.text {
          let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle,
                                          value: NSUnderlineStyle.single.rawValue,
                                          range: NSRange(location: 0, length: attributedString.length))
          attributedText = attributedString
        }
    }
}

Swift 3/4

// in swift 4 - switch NSUnderlineStyleAttributeName with NSAttributedStringKey.underlineStyle
extension UILabel {
    func underline() {
        if let textString = self.text {
          let attributedString = NSMutableAttributedString(string: textString)
          attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSRange(location: 0, length: attributedString.length))
          attributedText = attributedString
        }
    }
}


extension UIButton {
  func underline() {
    let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
    attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSRange(location: 0, length: (self.titleLabel?.text!.characters.count)!))
    self.setAttributedTitle(attributedString, for: .normal)
  }
}

Santinasantini

You should pass UTF16 count instead of the character count when creating your NSRange – Tedium

Answer 5

Just a little fix for the Shlome answer in Swift 4 and Xcode 9.

extension UILabel {
    func underline() {
        if let textString = self.text {
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedStringKey.underlineStyle,
                                          value: NSUnderlineStyle.styleSingle.rawValue,
                                          range: NSRange(location: 0, length: attributedString.length - 1))
            attributedText = attributedString
        }
    }
}

    extension UIButton {
        func underline() {
            let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
            attributedString.addAttribute(NSAttributedStringKey.underlineStyle,
                                          value: NSUnderlineStyle.styleSingle.rawValue,
                                          range: NSRange(location: 0, length: (self.titleLabel?.text!.count)!))
            self.setAttributedTitle(attributedString, for: .normal)
        }
    }

Headrest

You should pass UTF16 count instead of the character count when creating your NSRange – Tedium

Answer 6

You can underline the UILabel text using Interface Builder.

Here is the link of my answer : Adding underline attribute to partial text UILabel in storyboard

Cima

This method fails if you rebind the text to the label. – Dailey

@EricH What do you mean? – Levenson

Answer 7

Same Answer in Swift 4.2

For UILable

extension UILabel {
    func underline() {
        if let textString = self.text {
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle,
                                          value: NSUnderlineStyle.single.rawValue,
                                          range: NSRange(location: 0, length: textString.count))
            self.attributedText = attributedString
        }
    }
}

Call for UILabel like below

myLable.underline()

For UIButton

extension UIButton {
    func underline() {
        if let textString = self.titleLabel?.text {

            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle,
                                          value: NSUnderlineStyle.single.rawValue,
                                          range: NSRange(location: 0, length: textString.count))
            self.setAttributedTitle(attributedString, for: .normal)
        }

    }
}

Call for UIButton like below

myButton.underline()

I looked into above answers and some of them are force unwrapping text value. I will suggest to get value by safely unwrapping. This will avoid crash in case of nil value. Hope This helps :)

Barnard

simply beutiful and easy – Phototube

You should pass UTF16 count instead of the character count when creating your NSRange – Tedium

If you already have the extension for the UILabel, IMO it is simpler to call myButton.titleLabel?.underline(), or at least use it inside the underline() function in the extension for UIButton. – Hwahwan

Answer 8

Swift 4, 4.2 and 5.

  @IBOutlet weak var lblUnderLine: UILabel!

I need to underline particular text in UILabel. So, find range and set attributes.

    let strSignup = "Don't have account? SIGNUP NOW."
    let rangeSignUp = NSString(string: strSignup).range(of: "SIGNUP NOW.", options: String.CompareOptions.caseInsensitive)
    let rangeFull = NSString(string: strSignup).range(of: strSignup, options: String.CompareOptions.caseInsensitive)
    let attrStr = NSMutableAttributedString.init(string:strSignup)
    attrStr.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.white,
                           NSAttributedString.Key.font : UIFont.init(name: "Helvetica", size: 17)! as Any],range: rangeFull)
    attrStr.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.white,
                           NSAttributedString.Key.font : UIFont.init(name: "Helvetica", size: 20)!,
                          NSAttributedString.Key.underlineStyle: NSUnderlineStyle.thick.rawValue as Any],range: rangeSignUp) // for swift 4 -> Change thick to styleThick
    lblUnderLine.attributedText = attrStr

Output

Dorri

Answer 9

Underline to multiple strings in a sentence.

extension UILabel {
    func underlineMyText(range1:String, range2:String) {
        if let textString = self.text {

            let str = NSString(string: textString)
            let firstRange = str.range(of: range1)
            let secRange = str.range(of: range2)
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: firstRange)
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: secRange)
            attributedText = attributedString
        }
    }
}

Use by this way.

    lbl.text = "By continuing you agree to our Terms of Service and Privacy Policy."
    lbl.underlineMyText(range1: "Terms of Service", range2: "Privacy Policy.")

Woodwork

How you will track the touch? – Passant

Answer 10

Swift 4 changes. Remeber to use NSUnderlineStyle.styleSingle.rawValue instead of NSUnderlineStyle.styleSingle.

   'let attributedString = NSAttributedString(string: "Testing")
    let textRange = NSMakeRange(0, attributedString.length)
    let underlinedMessage = NSMutableAttributedString(attributedString: attributedString)
    underlinedMessage.addAttribute(NSAttributedStringKey.underlineStyle,
                                   value:NSUnderlineStyle.styleSingle.rawValue,
                                   range: textRange)
    label.attributedText = underlinedMessage

`

Warfeld

Answer 11

You can use this also if you want to achieve only half part of label as underline:- //For Swift 4.0+

let attributesForUnderLine: [NSAttributedString.Key: Any] = [
            .font: UIFont(name: AppFont.sourceSansPro_Regular, size: 12) ?? UIFont.systemFont(ofSize: 11),
            .foregroundColor: UIColor.blue,
            .underlineStyle: NSUnderlineStyle.single.rawValue]

        let attributesForNormalText: [NSAttributedString.Key: Any] = [
            .font: UIFont(name: AppFont.sourceSansPro_Regular, size: 12) ?? UIFont.systemFont(ofSize: 11),
            .foregroundColor: AppColors.ColorText_787878]

        let textToSet = "Want to change your preferences? Edit Now"
        let rangeOfUnderLine = (textToSet as NSString).range(of: "Edit Now")
        let rangeOfNormalText = (textToSet as NSString).range(of: "Want to change your preferences?")

        let attributedText = NSMutableAttributedString(string: textToSet)
        attributedText.addAttributes(attributesForUnderLine, range: rangeOfUnderLine)
        attributedText.addAttributes(attributesForNormalText, range: rangeOfNormalText)
        yourLabel.attributedText = attributedText

Salientian

Answer 12

The answer above is causing an error in my build environment.

This doesn't work in Swift 4.0:

attributedText.addAttribute(NSUnderlineStyleAttributeName, 
                            value: NSUnderlineStyle.styleSingle.rawValue, 
                            range: textRange)

Try this instead:

attributedText.addAttribute(NSAttributedStringKey.underlineStyle,
                            value: NSUnderlineStyle.styleSingle.rawValue,
                            range: textRange)

hope this helps someone.

Goldbrick

Answer 13

// Swift 4 Version

 let attributedString  = NSMutableAttributedString(string: "Your Text Here", attributes: [NSAttributedStringKey.underlineStyle : true])

self.yourlabel.attributedText = attributedString

Timms

Answer 14

A class to set and remove underline for UIbuttons for Swift 5. I hope this helps

import Foundation
   import UIKit

   class UiUtil {

       static let underlineThickness = 2
    
       class func removeUnderlineFromButton( _ button:UIButton ) {
          if let str = button.titleLabel?.attributedText {
            let attributedString = NSMutableAttributedString( attributedString: str )
            attributedString.removeAttribute(.underlineStyle, range: 
   NSRange.init(location: 0, length: attributedString.length))
            button.setAttributedTitle(attributedString, for: .normal)
         }
      }

    class func setUnderlineFromButton( _ button:UIButton ) {
        if let str = button.titleLabel?.attributedText {
            let attributedStringUnderline = NSMutableAttributedString( attributedString: 
    str  )
              attributedStringUnderline.addAttribute(
                NSAttributedString.Key.underlineStyle,
                value: underlineThickness,
                range: NSRange.init(location: 0, length: attributedStringUnderline.length)
              )
              button.setAttributedTitle(attributedStringUnderline, for: .normal)
           }
      }

   }

Delphine

Answer 15

I have algorithm that used in my app. In this algorithm you can underline substring even that have space between words

extension NSMutableAttributedString{

    static func  findSubStringAndUnderlineIt(subStringToBeFound : String,totalString : String)->  NSMutableAttributedString?{
        
        let attributedString = NSMutableAttributedString(string: totalString)

        var spaceCount = 0
        
        if subStringToBeFound.contains(" "){
            spaceCount = subStringToBeFound.components(separatedBy:" ").count-1
        }

        
        if  let range = attributedString.string.range(of: subStringToBeFound, options: .caseInsensitive){
        
            attributedString.addAttribute(NSAttributedString.Key.underlineStyle, value: NSUnderlineStyle.single.rawValue, range: NSMakeRange((range.lowerBound.utf16Offset(in: subStringToBeFound)) ,(range.upperBound.utf16Offset(in: subStringToBeFound)) +
            spaceCount))
                return attributedString
        }
        return attributedString
        
    }
    
}

in used section

 lblWarning.attributedText = NSMutableAttributedString.findSubStringAndUnderlineIt(subStringToBeFound:"Not: Sadece uygulamanın reklamları kaldırılacaktır.", totalString: lblWarning.text!)

Ette

Answer 16

For Swift 2.3

extension UIButton {
    func underline() {
        let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
        attributedString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleSingle.rawValue, range: NSRange(location: 0, length: (self.titleLabel?.text!.characters.count)!))
        self.setAttributedTitle(attributedString, forState: .Normal)
    }
}

and in ViewController

@IBOutlet var yourButton: UIButton!

in ViewDidLoad Method or in your function just write

yourButton.underline()

it will underline the title of your button

Deactivate