三種Swift實現單例模式的方法：全局變量，內部變量，dispatch_once方式
1. 全局變量
private let _singleton = Singleton() class Singleton: NSObject { class var sharedInstance: Singleton { get { return _singleton } } } 2. 內部變量
class Singleton { class var sharedInstance: Singleton { get { struct SingletonStruct { static let singleton: Singleton = Singleton() } return SingletonStruct.singleton } } } 3. dispatch_once方式
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內容了，希望大家能夠喜歡。
