Updated for Swift 3

Author: KelvinJin

DynamicFontSizeExample.xcodeproj/project.pbxproj

@@ -99,6 +99,8 @@
 				TargetAttributes = {
 					29F2024E1CA13E4E00AA0746 = {
 						CreatedOnToolsVersion = 7.3;
+						DevelopmentTeam = MG8YZ6JLG6;
+						LastSwiftMigration = 0800;
 					};
 				};
 			};
@@ -255,21 +257,25 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				DEVELOPMENT_TEAM = MG8YZ6JLG6;
 				INFOPLIST_FILE = DynamicFontSizeExample/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.Uthoft.DynamicFontSizeExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
 		};
 		29F202631CA13E4E00AA0746 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				DEVELOPMENT_TEAM = MG8YZ6JLG6;
 				INFOPLIST_FILE = DynamicFontSizeExample/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.Uthoft.DynamicFontSizeExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 3.0;
 			};
 			name = Release;
 		};

DynamicFontSizeExample/AppDelegate.swift

@@ -14,30 +14,30 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     var window: UIWindow?
 
 
-    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
+    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
         // Override point for customization after application launch.
         return true
     }
 
-    func applicationWillResignActive(application: UIApplication) {
+    func applicationWillResignActive(_ application: UIApplication) {
         // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
         // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
     }
 
-    func applicationDidEnterBackground(application: UIApplication) {
+    func applicationDidEnterBackground(_ application: UIApplication) {
         // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
         // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
     }
 
-    func applicationWillEnterForeground(application: UIApplication) {
+    func applicationWillEnterForeground(_ application: UIApplication) {
         // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
     }
 
-    func applicationDidBecomeActive(application: UIApplication) {
+    func applicationDidBecomeActive(_ application: UIApplication) {
         // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
     }
 
-    func applicationWillTerminate(application: UIApplication) {
+    func applicationWillTerminate(_ application: UIApplication) {
         // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
     }
 

DynamicFontSizeHelper.swift

@@ -1,19 +1,19 @@
 import UIKit
 
 private var fontSizeMultiplier : CGFloat {
-    switch UIApplication.sharedApplication().preferredContentSizeCategory {
-    case UIContentSizeCategoryAccessibilityExtraExtraExtraLarge: return 23 / 16
-    case UIContentSizeCategoryAccessibilityExtraExtraLarge: return 22 / 16
-    case UIContentSizeCategoryAccessibilityExtraLarge: return 21 / 16
-    case UIContentSizeCategoryAccessibilityLarge: return 20 / 16
-    case UIContentSizeCategoryAccessibilityMedium: return 19 / 16
-    case UIContentSizeCategoryExtraExtraExtraLarge: return 19 / 16
-    case UIContentSizeCategoryExtraExtraLarge: return 18 / 16
-    case UIContentSizeCategoryExtraLarge: return 17 / 16
-    case UIContentSizeCategoryLarge: return 1.0
-    case UIContentSizeCategoryMedium: return 15 / 16
-    case UIContentSizeCategorySmall: return 14 / 16
-    case UIContentSizeCategoryExtraSmall: return 13 / 16
+    switch UIApplication.shared.preferredContentSizeCategory {
+    case UIContentSizeCategory.accessibilityExtraExtraExtraLarge: return 23 / 16
+    case UIContentSizeCategory.accessibilityExtraExtraLarge: return 22 / 16
+    case UIContentSizeCategory.accessibilityExtraLarge: return 21 / 16
+    case UIContentSizeCategory.accessibilityLarge: return 20 / 16
+    case UIContentSizeCategory.accessibilityMedium: return 19 / 16
+    case UIContentSizeCategory.extraExtraExtraLarge: return 19 / 16
+    case UIContentSizeCategory.extraExtraLarge: return 18 / 16
+    case UIContentSizeCategory.extraLarge: return 17 / 16
+    case UIContentSizeCategory.large: return 1.0
+    case UIContentSizeCategory.medium: return 15 / 16
+    case UIContentSizeCategory.small: return 14 / 16
+    case UIContentSizeCategory.extraSmall: return 13 / 16
     default: return 1.0
     }
 }
@@ -27,37 +27,37 @@ private class ContentSizeCategoryChangeManager {
         weak var object: AnyObject?
         var block: ContentSizeCategoryDidChangeCallback
 
-        init(object: AnyObject, block: ContentSizeCategoryDidChangeCallback) {
+        init(object: AnyObject, block: @escaping ContentSizeCategoryDidChangeCallback) {
             self.object = object
             self.block = block
         }
     }
 
-    private var observerPool: [Observer] = []
+    fileprivate var observerPool: [Observer] = []
 
-    private init() {
-        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(contentSizeCategoryDidChange(_:)), name: UIContentSizeCategoryDidChangeNotification, object: nil)
+    fileprivate init() {
+        NotificationCenter.default.addObserver(self, selector: #selector(contentSizeCategoryDidChange(_:)), name: NSNotification.Name.UIContentSizeCategoryDidChange, object: nil)
     }
 
-    func addCallback(observer: AnyObject, block: ContentSizeCategoryDidChangeCallback) {
+    func addCallback(_ observer: AnyObject, block: @escaping ContentSizeCategoryDidChangeCallback) {
         // Don't readd the call back.
-        guard !observerPool.contains({ $0.object === observer }) else { return }
+        guard !observerPool.contains(where: { $0.object === observer }) else { return }
 
         // Run the block once to make sure the font size is initialized correctly.
         block()
 
         observerPool.append(Observer(object: observer, block: block))
     }
 
-    @objc func contentSizeCategoryDidChange(notification: NSNotification) {
-        dispatch_async(dispatch_get_main_queue()) { [unowned self] in
+    @objc func contentSizeCategoryDidChange(_ notification: Notification) {
+        DispatchQueue.main.async { [unowned self] in
             self.observerPool = self.observerPool.filter { $0.object != nil }
             self.observerPool.forEach { $0.block() }
         }
     }
 
     deinit {
-        NSNotificationCenter.defaultCenter().removeObserver(self)
+        NotificationCenter.default.removeObserver(self)
     }
 }
 
@@ -66,12 +66,12 @@ protocol FontSizeScalable: class {
 }
 
 extension FontSizeScalable {
-    private func registerForSizeChange(defaultFontSize: CGFloat? = nil) {
+    fileprivate func registerForSizeChange(_ defaultFontSize: CGFloat? = nil) {
         let defaultFontSize = defaultFontSize ?? scalableFont.pointSize
 
         ContentSizeCategoryChangeManager.sharedInstance.addCallback(self) { [weak self] _ in
             guard let _self = self else { return }
-            _self.scalableFont = UIFont(descriptor: _self.scalableFont.fontDescriptor(), size: defaultFontSize * fontSizeMultiplier)
+            _self.scalableFont = UIFont(descriptor: _self.scalableFont.fontDescriptor, size: defaultFontSize * fontSizeMultiplier)
         }
     }
 }