三种Swift实现单例模式的方法:全局变量,内部变量,dispatch_once方式
1. 全局变量
? 1 2 3 4 5 6 7 8 private let _singleton = Singleton() class Singleton: NSObject { class var sharedInstance: Singleton { get { return _singleton } } }2. 内部变量
? 1 2 3 4 5 6 7 8 9 10 class Singleton { class var sharedInstance: Singleton { get { struct SingletonStruct { static let singleton: Singleton = Singleton() } return SingletonStruct.singleton } } }3. dispatch_once方式
? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 class Singleton { class var sharedInstance: Singleton { get { struct SingletonStruct { static var onceToken:dispatch_once_t = 0 static var singleton: Singleton? = nil } dispatch_once(&SingletonStruct.onceToken, { () -> Void in SingletonStruct.singleton = Singleton() }) return SingletonStruct.singleton! } } }以上所述就是本文的全部内容了,希望大家能够喜欢。