Implementing an MVC Architecture in iOS using a Singleton Pattern (written in Swift)

SingletonPatternMVC.swift

// ------------------------------------------------------------------------------------->
// This example is comprised of three swift files demonstrating how to implement an MVC
// architecture using the singleton pattern in iOS. By using a singleton pattern one can 
// create a simple class (or classes) to serve as the model for an application
// and ensure that only one instance of that class is created and that it is accessible
// globally. We do this by creating a 'shared' property to make access to the single 
// instance global, and initialize the class privately to ensure that only one instance
// is ever created. While creating this simple app/gist I used the following blog post
// from Bart Jacobs at cocoacasts.com for guidance (Thanks Bart!): 
// 
//     "What is a Singleton How to Create One in Swift" 
//     https://cocoacasts.com/what-is-a-singleton-and-how-to-create-one-in-swift
//
// ------------------------------------------------------------------------------------->





//
//  SingletonModel.swift
//  SingletonApp
//
//  Created by Christopher Pedersen on 8/6/18.
//  Copyright © 2018 Christopher Pedersen. All rights reserved.
//

import Foundation

class SingletonModel {
    // Declare a 'shared' property  which will allow a single
    // instance of SingletonModel to be used globally anywhere
    // within our application.
    static let shared = SingletonModel()
    
    // Create a property to store application state in our model
    var myProperty: String
    
    // Privately initialize SingletonModel so that multiple
    // instances cannot be created. Using this singleton
    // design allows us to create a single global which will
    // serve as the model for our application.
    private init() {
        self.myProperty = "FOO"
    }
}





//
//  ViewController.swift
//  SingletonApp
//
//  Created by Christopher Pedersen on 8/6/18.
//  Copyright © 2018 Christopher Pedersen. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        mainLabel.text = SingletonModel.shared.myProperty
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBOutlet weak var mainLabel: UILabel!
}





//
//  SecondaryViewController.swift
//  SingletonApp
//
//  Created by Christopher Pedersen on 8/6/18.
//  Copyright © 2018 Christopher Pedersen. All rights reserved.
//

import Foundation
import UIKit

class SecondaryViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        // mainLabel.text = SingletonModel.shared.myProperty
        SingletonModel.shared.myProperty = "BAR"
        secondaryLabel.text = SingletonModel.shared.myProperty
        
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBOutlet weak var secondaryLabel: UILabel!
    
}