ViewControllerViewChangeBackgroundColor.swift

import UIKit

class ViewControllerView: UIView {
    
    private lazy var buttonStack: UIStackView = {
        let stack = UIStackView(arrangedSubviews: [viewButton, alertButton])
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.spacing = 12
        stack.axis = .vertical
        return stack
    }()
    
    private lazy var viewButton: UIButton = makeButton(with: "Change backgroundColor")
    private lazy var alertButton = makeButton(with: "Present Alert")
    
    init(viewColor: UIColor) {
        super.init(frame: .zero)
        viewButton.addTarget(self, action: #selector(changeBackgroundColor), for: .touchUpInside)
        subviews()
        self.backgroundColor = viewColor
    }
    
    required init?(coder: NSCoder) {
        fatalError("This is a programmatic view")
    }
    
    private func subviews() {
        addSubview(buttonStack)
        constraints()
    }
    
    private func constraints() {
        NSLayoutConstraint.activate([
            buttonStack.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -20),
            buttonStack.leadingAnchor.constraint(equalTo: safeAreaLayoutGuide.leadingAnchor, constant: 20),
            buttonStack.trailingAnchor.constraint(equalTo: safeAreaLayoutGuide.trailingAnchor, constant: -20)
        ])
    }
    
    /// Make a button with the given `title`, `backgroundColor`, and `UIButton.ButtonType`
    private func makeButton(with title: String, backgroundColor: UIColor = .white, type: UIButton.ButtonType = .system) -> UIButton {
        let button = UIButton(type: type)
        button.setTitle(title, for: .normal)
        button.backgroundColor = backgroundColor
        button.layer.cornerRadius = 10
        return button
    }
    
    @objc private func changeBackgroundColor() {
        backgroundColor = .orange
    }
}