Add NSUnderlineStyle.PatternDash to NSAttributedString in Swift?

Question

I'm trying to add an underline to some text in my Swift app. This is the code I have currently:

let text = NSMutableAttributedString(string: self.currentHome.name)

let attrs = [NSUnderlineStyleAttributeName:NSUnderlineStyle.PatternDash]

text.addAttributes(attrs, range: NSMakeRange(0, text.length))
homeLabel.attributedText = text

But I get this error on the text.addAttributes line:

NSString is not identical to NSObject

How can I add an attribute contained in an enum to an NSMutableAttributedString in Swift?

Komsomol

https://mcmap.net/q/658570/-how-to-use-nsunderlinestyle-patterndot – Fultz

Answer 1

Here's a full example of creating a UILabel with underlined text:

Swift 5:

let homeLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 30))

let text = NSMutableAttributedString(string: "hello, world!")

let attrs = [NSAttributedString.Key.underlineStyle: NSUnderlineStyle.patternDash.rawValue | NSUnderlineStyle.single.rawValue]

text.addAttributes(attrs, range: NSRange(location: 0, length: text.length))

homeLabel.attributedText = text

---

Swift 4:

let homeLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 30))

let text = NSMutableAttributedString(string: "hello, world!")

let attrs = [NSAttributedStringKey.underlineStyle: NSUnderlineStyle.patternDash.rawValue | NSUnderlineStyle.styleSingle.rawValue]

text.addAttributes(attrs, range: NSRange(location: 0, length: text.length))

homeLabel.attributedText = text

---

Swift 2:

Swift allows you to pass an Int to a method that takes an NSNumber, so you can make this a little cleaner by removing the conversion to NSNumber:

text.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleDouble.rawValue, range: NSMakeRange(0, text.length))

Note: This answer previously used toRaw() as used in the original question, but that is now incorrect as toRaw() has been replaced by the property rawValue as of Xcode 6.1.

Groark

can you please, update your code with swift4 syntax. – Fantasist

Value of type 'NSAttributedString' has no member 'addAttributes'; – Mercy

@BenShabat, you should an NSMutableAttributedString. – Groark

Answer 2

If you want an actual dashed line, you should OR | the raw values of both PatternDash and StyleSingle enums like below:

let dashed     =  NSUnderlineStyle.PatternDash.rawValue | NSUnderlineStyle.StyleSingle.rawValue

let attribs    = [NSUnderlineStyleAttributeName : dashed, NSUnderlineColorAttributeName : UIColor.whiteColor()];

let attrString =  NSAttributedString(string: plainText, attributes: attribs)

Heiney

Answer 3

In Xcode 6.1, SDK iOS 8.1 toRaw() has been replaced by rawValue:

 text.addAttribute(NSUnderlineStyleAttributeName, value:  NSUnderlineStyle.StyleDouble.rawValue, range: NSMakeRange(0, text.length))

Or Easier :

 var text : NSAttributedString = NSMutableAttributedString(string: str, attributes : [NSUnderlineStyleAttributeName: NSUnderlineStyle.StyleSingle.rawValue]) 

Susy

Answer 4

Turns out I needed the toRaw() method - this works:

text.addAttribute(NSUnderlineStyleAttributeName, value: NSNumber(integer:(NSUnderlineStyle.StyleDouble).toRaw()), range: NSMakeRange(0, text.length))

Komsomol