通常给UILabel设置文本，我们都是设置属性UILabel.text。这意味着显示的文本是单一的，整个文本只能有一种同样的文本效果。而另外一个属性UILabel.attributedText，就可以可以分段设置的不同的字体、阴影效果等，比如前几个字为一个阴影效果，后几个字使用下划线效果。

如下代码我做了些改变，以便在Swift 3.0上可以运行，本来的代码来自 https://makeapppie.com/2016/07/05/using-attributed-strings-in-swift-3-0/ ，

可以运行起来，查看效果：

import UIKit@UIApplicationMainclass AppDelegate: UIResponder, UIApplicationDelegate {    var window: UIWindow?    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {        self.window = UIWindow(frame: UIScreen.main.bounds)        let page = Page()        page.view.backgroundColor = .white        self.window!.rootViewController = page        self.window?.makeKeyAndVisible()        return true    }}class Page: UIViewController {    override func viewDidLoad() {        super.viewDidLoad()        let myLabel = UILabel()        let myString = "P is for Pizza and Pizza is for me"        view.backgroundColor = UIColor.white        //initialize the label to be the entire view        //and to word wrap        myLabel.frame = view.bounds.insetBy(dx: 20, dy: 20)        //mylabel.frame.size.width = 350.0//uncomment for playgrounds        myLabel.lineBreakMode = .byWordWrapping        myLabel.numberOfLines = 0//        myLabel.backgroundColor = UIColor.yellow        myLabel.text = myString        view.addSubview(myLabel)        //: Initialize the mutable string        let myMutableString = NSMutableAttributedString(            string: myString,            attributes: [NSFontAttributeName:                UIFont(name: "Georgia", size: 18.0)!])        // for first Pizza        myMutableString.addAttribute(            NSFontAttributeName,            value: UIFont(                name: "Chalkduster",                size: 24.0)!,            range: NSRange(                location: 9,                length: 5))        //: Make a big blue P        myMutableString.addAttribute(            NSFontAttributeName,            value: UIFont(                name: "AmericanTypewriter-Bold",                size: 36.0)!,            range: NSRange(                location:0,                length:1))        myMutableString.addAttribute(            NSForegroundColorAttributeName,            value: UIColor.blue,            range: NSRange(                location:0,                length:1))        //: Make the second pizza red and outlined in Helvetica Neue        myMutableString.addAttribute(            NSFontAttributeName,            value: UIFont(                name: "Helvetica Neue",                size: 36.0)!,            range: NSRange(                location: 19,                length: 5))        myMutableString.addAttribute(            NSStrokeColorAttributeName,            value: UIColor.red,            range:  NSRange(                location: 19,                length: 5))        myMutableString.addAttribute(            NSStrokeWidthAttributeName,            value: 4,            range: NSRange(                location: 19,                length: 5))        //: Set the background color is attributes text.        //: which is not the color of the background text.        let  stringLength = myString.characters.count        myMutableString.addAttribute(NSBackgroundColorAttributeName,                                     value: UIColor.magenta,                                     range: NSRange(                                        location: 0,                                        length: stringLength))        //: Add a Drop Shadow        //: Make the Drop Shadow        let shadow = NSShadow()        shadow.shadowOffset = CGSize(width: 5, height: 5)        shadow.shadowBlurRadius = 5        shadow.shadowColor = UIColor.gray        //: Add a drop shadow to the text        myMutableString.addAttribute(            NSShadowAttributeName,            value: shadow,            range: NSRange(                location: 27,                length: 7))        //:Change to 48 point Menlo        myMutableString.addAttribute(            NSFontAttributeName,            value: UIFont(                name: "Menlo",                size: 48.0)!,            range: NSRange(                location: 27,                length: 7))        //: Appending the String with !!! and an Attributed String        let myAddedStringAttributes:[String:AnyObject]? = [            NSFontAttributeName:UIFont(                name: "AvenirNext-Heavy",                size: 48.0)!,            NSForegroundColorAttributeName:UIColor.red,            NSShadowAttributeName: shadow        ]        let myAddedString = NSAttributedString(            string: "!!!",            attributes: myAddedStringAttributes)        myMutableString.append(myAddedString)        //: Apply to the label        myLabel.attributedText = myMutableString    }}

相当的具有表现力。