swift中单例的写法

Swift中单例的写法常见有两种：
1.这种方式较简洁，推荐使用

//  
//  MyManegerOne.swift  
//  swift_SingleInstance  
//  
//  Created by MrZhaoCn on 16/12/5.  
//  Copyright © 2016年 MrZhaoCn. All rights reserved.  
//  单例写法1，推荐这种，简单  
  
import UIKit  
class MyManegerOne: NSObject {  
    private static let shareInstance = MyManegerOne()  
    class func shareManeger() ->MyManegerOne {  
        return shareInstance  
    }  
} 

2.这种方式也可以，相比于第一种推荐前者

//  
//  MyManegerTwo.swift  
//  swift_SingleInstance  
//  
//  Created by MrZhaoCn on 16/12/5.  
//  Copyright © 2016年 MrZhaoCn. All rights reserved.  
// 单例写法2  
  
import UIKit  
class MyManegerTwo: NSObject {  
        class func sharedManager() ->MyManegerTwo {  
            struct Static {  
                static let instance : MyManegerTwo = MyManegerTwo()  
            }  
            return Static.instance  
    }  
}  

下面在控制器里面测试一下

import UIKit  
class ViewController: UIViewController {  
    override func viewDidLoad() {  
        super.viewDidLoad()     
        let myManeger = MyManegerOne.shareManeger()  
        print(myManeger)  
        let myManeger1 = MyManegerOne.shareManeger()  
        print(myManeger1)  
          
        let myManegerTwo = MyManegerTwo.sharedManager()  
        print(myManegerTwo)  
        let myManegerTwo1 = MyManegerTwo.sharedManager()  
        print(myManegerTwo1)  
    }  
}  

打印结果：可以看出正确的实现了swift中的单例:

20161221155829649.png