Singleton in Swift

Question

I\'ve been trying to implement a singleton to be used as a cache for photos which I uploaded to my iOS app from the web. I\'ve attached three variants in the code below. I

Answer 1

Following are the two different approaches to create your singleton class in swift 2.0

Approach 1) This approach is Objective C implementation over swift.

import UIKit

class SomeManager: NSObject {

       class var sharedInstance : SomeManager {

              struct managerStruct {

                   static var onceToken : dispatch_once_t = 0
                   static var sharedObject : SomeManager? = nil
              }

              dispatch_once(&managerStruct.onceToken) { () -> Void in
                   managerStruct.sharedObject = SomeManager()
              }
              return managerStruct.sharedObject!
       }

       func someMethod(){
              print("Some method call")
       }
 }

Approach 2) One line Singleton, Don't forget to implement the Private init (restrict usage of only singleton)

import UIKit

class SomeManager: NSObject {

       static let sharedInstance = SomeManager()

       private override init() {

       }

       func someMethod(){
            print("Some method call")
       }
  }

Call the Singleton method like :

  SomeManager.sharedInstance.someMethod()