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
private let _singleton = Singleton() class Singleton: NSObject {
class var sharedInstance: Singleton {
get {
return _singleton }
}
}
2. 内部变量
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内容了,希望大家能够喜欢。