Solving Protocol issue using an abstract class

gistfile1.swift

// Playground - noun: a place where people can play

import UIKit

class MyItem { /* some model properties */ }

protocol ItemViewProtocol: class {
    // some protocol methods (e.g. updateWithItem(), etc)
    func setupItem(item: MyItem)
    init(String)
}


class ItemView: UIView, ItemViewProtocol {
    required init(_: String) {
        super.init()
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setupItem(item: MyItem) {
        
    }
}


class SpecificItemView: ItemView {
    override func setupItem(item: MyItem) {
        // do item setup
    }
}

class AnotherItemView: ItemView {
    override func setupItem(item: MyItem) {
        // do DIFFERENT item setup
    }
}


class MyViewController: UIViewController {
    
    var itemView: ItemView = SpecificItemView("ok") as ItemView
    
    override func viewDidLoad() {
        itemView.setupItem(MyItem())
        itemView.removeFromSuperview()
    }
}