extension String {
//MARK: Getting customized string
struct StringAttribute {
    var fontName = "HelveticaNeue-Bold"
    var fontSize: CGFloat?
    var initialIndexOftheText = 0
    var lastIndexOftheText: Int?
    var textColor: UIColor = .black
    var backGroundColor: UIColor = .clear
    var underLineStyle: NSUnderlineStyle = .styleNone
    var textShadow: TextShadow = TextShadow()

    var fontOfText: UIFont {
        if let font = UIFont(name: fontName, size: fontSize!) {
            return font
        } else {
            return UIFont(name: "HelveticaNeue-Bold", size: fontSize!)!
        }
    }

    struct TextShadow {
        var shadowBlurRadius = 0
        var shadowOffsetSize = CGSize(width: 0, height: 0)
        var shadowColor: UIColor = .clear
    }
}
func getFontifiedText(partOfTheStringNeedToConvert partTexts: [StringAttribute]) -> NSAttributedString {
    let fontChangedtext = NSMutableAttributedString(string: self, attributes: [NSFontAttributeName: UIFont(name: "HelveticaNeue-Bold", size: (partTexts.first?.fontSize)!)!])
    for eachPartText in partTexts {
        let lastIndex = eachPartText.lastIndexOftheText ?? self.count
        let attrs = [NSFontAttributeName : eachPartText.fontOfText, NSForegroundColorAttributeName: eachPartText.textColor, NSBackgroundColorAttributeName: eachPartText.backGroundColor, NSUnderlineStyleAttributeName: eachPartText.underLineStyle, NSShadowAttributeName: eachPartText.textShadow ] as [String : Any]
        let range = NSRange(location: eachPartText.initialIndexOftheText, length: lastIndex - eachPartText.initialIndexOftheText)
        fontChangedtext.addAttributes(attrs, range: range)
    }
    return fontChangedtext
}

}

//像下面这样使用它

    let someAttributedText = "Some   Text".getFontifiedText(partOfTheStringNeedToConvert: <#T##[String.StringAttribute]#>)

Swift使用与Obj-C相同的NSMutableAttributedString。你通过传入计算值作为字符串来实例化它:

var attributedString = NSMutableAttributedString(string:"\(calculatedCoffee)")

现在创建带属性的g字符串。注意:UIFont.systemFontOfSize(_)现在是一个可失败的初始化式，所以在你可以使用它之前，它必须被解除包装:

var attrs = [NSFontAttributeName : UIFont.systemFontOfSize(19.0)!]
var gString = NSMutableAttributedString(string:"g", attributes:attrs)

然后追加:

attributedString.appendAttributedString(gString)

然后你可以像这样设置UILabel来显示NSAttributedString:

myLabel.attributedText = attributedString

斯威夫特3、4、5所示

使用下面的代码为文本颜色，字体，背景颜色和下划线/下划线颜色

    let text = "swift is language"
    let attributes = [NSAttributedString.Key.foregroundColor: UIColor.red, NSAttributedString.Key.backgroundColor: UIColor.blue,NSAttributedString.Key.font: UIFont.systemFont(ofSize: 25.0),NSAttributedString.Key.underlineColor: UIColor.white,NSAttributedString.Key.underlineStyle: NSUnderlineStyle.single.rawValue] as [NSAttributedString.Key : Any]
        
    let textAttribute = NSAttributedString(string: text, attributes: attributes)
    swiftLabel1.attributedText = textAttribute

我强烈建议使用带属性字符串的库。当你想要，例如，一个字符串有四种不同的颜色和四种不同的字体时，它使它变得更容易。这是我最喜欢的。它被称为SwiftyAttributes

如果你想用SwiftyAttributes创建一个有四种不同颜色和不同字体的字符串:

let magenta = "Hello ".withAttributes([
    .textColor(.magenta),
    .font(.systemFont(ofSize: 15.0))
    ])
let cyan = "Sir ".withAttributes([
    .textColor(.cyan),
    .font(.boldSystemFont(ofSize: 15.0))
    ])
let green = "Lancelot".withAttributes([
    .textColor(.green),
    .font(.italicSystemFont(ofSize: 15.0))

    ])
let blue = "!".withAttributes([
    .textColor(.blue),
    .font(.preferredFont(forTextStyle: UIFontTextStyle.headline))

    ])
let finalString = magenta + cyan + green + blue

finalString将显示为

属性可以直接设置在swift 3…

    let attributes = NSAttributedString(string: "String", attributes: [NSFontAttributeName : UIFont(name: "AvenirNext-Medium", size: 30)!,
         NSForegroundColorAttributeName : UIColor .white,
         NSTextEffectAttributeName : NSTextEffectLetterpressStyle])

然后在任何具有属性的类中使用该变量

Swift: xcode 6.1

    let font:UIFont? = UIFont(name: "Arial", size: 12.0)

    let attrString = NSAttributedString(
        string: titleData,
        attributes: NSDictionary(
            object: font!,
            forKey: NSFontAttributeName))