Delegate Example

playground.swift

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

import UIKit
import Foundation
import PlaygroundSupport

protocol MyDelegate: class {
	func didTapButton()
}

class MyViewController: UIViewController {

	lazy var myView: MyView = {
		let view = MyView(frame: CGRect(x: 0, y: 0, width: 300, height: 100))
		view.delegate = self
		view.backgroundColor = .red
		return view
	}()

	override func viewDidLoad() {
		super.viewDidLoad()
		view.addSubview(myView)
	}

}

extension MyViewController: MyDelegate {
	func didTapButton() {
		print("Pressed")
	}
}

class MyView: UIView {
	weak var delegate: MyDelegate?

	var button: UIButton = {
		let button = UIButton(frame: CGRect(x: 10, y: 10, width: 50, height: 30))
		button.setTitle("Hi", for: .normal)
		button.setTitleColor(.black, for: .normal)
		button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
		button.backgroundColor = .white
		return button
	}()

	override func layoutSubviews() {
		super.layoutSubviews()
		addSubview(button)
	}

	func buttonTapped() {
		delegate?.didTapButton()
	}
}

PlaygroundPage.current.liveView = MyViewController()