Sample view controller that is instantiated using xibs.

SampleViewController.swift

//
//  SampleViewController.swift
//  MediumSamples
//
//  Created by Fernando Ortiz on 1/4/17.
//  Copyright © 2017 Fernando Martín Ortiz. All rights reserved.
//

import UIKit

class SampleViewController: UIViewController {
    
    // This Very important attribute is necessary for this view controller
    // to perform some actions.
    //
    // Note that, in this case, this attribute is declared as 'let', 
    // it's IMMUTABLE.
    let veryImportantAttribute: String

    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    // In this custom initializer we can send dependencies that are needed
    // from this view controller to work properly.
    // We simply can't forget to pass data. In that case, the project won't compile.
    init(veryImportantAttribute: String) {
        self.veryImportantAttribute = veryImportantAttribute
        super.init(nibName: "SampleViewController", bundle: nil)
    }
    
    // This will be never called, so we don't need to care
    // about its implementation.
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}