Swift 4 Label attributes

Question

I\'m moving from swift 3 to swift 4. I have UILabels that I am giving very specific text properties to the label. I\'m getting an \'unexpectedly found nil while unwrapping

Answer 1

@Larme's comment about the .rawValue not being needed is correct.

Also, you can avoid the force cast that crashes your code using explicit typing:

let strokeTextAttributes: [NSAttributedString.Key: Any] = [
    .strokeColor : UIColor.black,
    .foregroundColor : UIColor.white,
    .strokeWidth : -2.0,
    .font : UIFont.boldSystemFont(ofSize: 18)
]

This gets rid of the repetitive NSAttributedString.Key., too.

Answer 2

In Swift 4.0+, attributed string accepts json (dictionary) with key type NSAttributedStringKey or NSAttributedString.Key.

So you must change it from [String : Any] to

Swift 4.1 & below - [NSAttributedStringKey : Any] &
Swift 4.2 & above - [NSAttributedString.Key : Any]

Swift 4.2

Initialiser for AttributedString in Swift 4.2 is changed to [NSAttributedString.Key : Any]?

public init(string str: String, attributes attrs: [NSAttributedString.Key : Any]? = nil)

Here is sample working code.

let label = UILabel()
let labelText = "String Text"

let strokeTextAttributes = [
     NSAttributedString.Key.strokeColor : UIColor.black,
     NSAttributedString.Key.foregroundColor : UIColor.white,
     NSAttributedString.Key.strokeWidth : -2.0,
     NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 18)
   ] as [NSAttributedString.Key : Any]

label.attributedText = NSAttributedString(string: labelText, attributes: strokeTextAttributes)

Swift 4.0

Initialiser for AttributedString in Swift 4.0 is changed to [NSAttributedStringKey : Any]?.

public init(string str: String, attributes attrs: [NSAttributedStringKey : Any]? = nil)

Here is sample working code.

let label = UILabel()
let labelText = "String Text"

let strokeTextAttributes = [
     NSAttributedStringKey.strokeColor : UIColor.black,
     NSAttributedStringKey.foregroundColor : UIColor.white,
     NSAttributedStringKey.strokeWidth : -2.0,
     NSAttributedStringKey.font : UIFont.boldSystemFont(ofSize: 18)
   ] as [NSAttributedStringKey : Any]

label.attributedText = NSAttributedString(string: labelText, attributes: strokeTextAttributes)

Look at this Apple Document, for more info: NSAttributedString - Creating an NSAttributedString Object

Answer 3

NSAttributedStringKey.strokeColor.rawValue is of type String

NSAttributedStringKey.strokeColor is of type NSAttributedStringKey

So its unable to convert String to NSAttributedStringKey . You have to use like below:

let strokeTextAttributes: [NSAttributedStringKey : Any] = [
    NSAttributedStringKey.strokeColor : UIColor.black,
    NSAttributedStringKey.foregroundColor : UIColor.white,
    NSAttributedStringKey.strokeWidth : -2.0,
    NSAttributedStringKey.font : UIFont.boldSystemFont(ofSize: 18)
]

Answer 4

Swift 4 Attributed text with multiple colors

extension NSMutableAttributedString 
{
@discardableResult func DustyOrange(_ text: String, Fontsize : CGFloat) -> NSMutableAttributedString 
{
    let attrs: [NSAttributedStringKey: Any] = [.font: UIFont(name: "SFUIDisplay-Regular", size: Fontsize)!, NSAttributedStringKey.foregroundColor: UIColor(red: 242.0/255.0, green: 97.0/255.0, blue: 0.0/255.0, alpha: 1.0) ]
    let boldString = NSMutableAttributedString(string:text, attributes: attrs)
    append(boldString)
    return self
}
@discardableResult func WarmGrey(_ text: String, Fontsize : CGFloat) -> NSMutableAttributedString {
    let attrs: [NSAttributedStringKey: Any] = [.font: UIFont(name: "SFUIDisplay-Regular", size: Fontsize)!, NSAttributedStringKey.foregroundColor: UIColor(red: 152.0/255.0, green: 152.0/255.0, blue: 152.0/255.0, alpha: 1.0) ]
    let boldString = NSMutableAttributedString(string:text, attributes: attrs)
    append(boldString)
    return self
}
}

Now you can Execute the function something like this to use as a globally

func FormattedString(Orange : String, WarmGrey : String ,fontsize : CGFloat) -> NSMutableAttributedString 
{
   let paragraphStyle = NSMutableParagraphStyle()
   paragraphStyle.alignment = .left
   paragraphStyle.lineSpacing = 1
   paragraphStyle.paragraphSpacing = 1
   let formattedString = NSMutableAttributedString()
   formattedString
    .DustyOrange(Orange, Fontsize: fontsize)
    .WarmGrey(WarmGrey, Fontsize: fontsize )
  formattedString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle], range: NSRange(location: 0, length: formattedString.length))
   return formattedString
}

You can use globalized function like this

 yourLabelName.attributedText = FormattedString(Orange: "String with orange color", WarmGrey: " String with warm grey color.", fontsize: 11.5)

Attributed text with image

func AttributedTextwithImgaeSuffix(AttributeImage : UIImage , AttributedText : String , buttonBound : UIButton) -> NSMutableAttributedString 
 {
   let fullString = NSMutableAttributedString(string: AttributedText + "  ")
   let image1Attachment = NSTextAttachment()
   image1Attachment.bounds = CGRect(x: 0, y: ((buttonBound.titleLabel?.font.capHeight)! - 
  AttributeImage.size.height).rounded() / 2, width: 
  AttributeImage.size.width, height: AttributeImage.size.height)
  image1Attachment.image = AttributeImage
  let image1String = NSAttributedString(attachment: image1Attachment)
  fullString.append(image1String)
  fullString.append(NSAttributedString(string: ""))
  return fullString 
}

you can use "NSTextAttachment" with your button label like this.

   yourUIButton.setAttributedTitle(AttributedTextwithImgaeSuffix(AttributeImage: desiredImage, AttributedText: "desired UIButton title", buttonBound: yourUIButton), for: .normal)

Answer 5

if you want to change particular string value so that below answer is helpful you:-

let subStr = "Hello" let allStr = "Hello World"

    let newStr = NSMutableAttributedString(string: allStr)
    newStr.addAttribute(kCTFontAttributeName as NSAttributedStringKey, value:  UIFont.init(customFont: .MyriadPro_R, withSize: 18)!, range: (allStr as NSString).range(of: subStr))
    newStr.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor.PrimaryColor, range: (allStr as NSString).range(of: subStr))
    self.stateLbl.attributedText = newStr

Answer 6

let text = systolicString + " / " + diastolicString

let newStr = NSMutableAttributedString(string: text)
// I have static ranges, but you can also extract them dynamically
let systolicRange = NSRange(location: 0, length: 2)
let backslashRange = NSRange(location: 3, length: 1)
let diastolicRange = NSRange(location: 5, length: 2)

newStr.addAttribute(NSAttributedStringKey.font, value:  UIFont.ubuntuRegular(28), range: systolicRange)
newStr.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor(hexString: "042f57"), range: systolicRange)

newStr.addAttribute(NSAttributedStringKey.font, value:  UIFont.ubuntuLight(23), range: backslashRange)
newStr.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor(hexString: "6485a3"), range: backslashRange)

newStr.addAttribute(NSAttributedStringKey.font, value:  UIFont.ubuntuRegular(18), range: diastolicRange)
newStr.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor(hexString: "042f57"), range: diastolicRange)
// my UILabel
valueLabel.attributedText = newStr