A iOS UIButton subclass with support for background colors

BackgroundColorButton.swift

//
//  LICENSE: MIT
//  Source: https://gist.github.com/acrookston/af50c921089b93d1d71e7a9349dc7af7
//  Created by Andrew C on 4/16/17.
//  Copyright © 2017 Andrew Crookston. All rights reserved.
//

import UIKit

extension UIControlState: Hashable {
    public var hashValue: Int { return Int(rawValue) }
}

class BackgroundColorButton: UIButton {
    func setBackgroundColors(_ options: [UIControlState: UIColor]) {
        colors = options
        updateBackgroundColor()
    }

    func setBackgroundColor(_ color: UIColor, for state: UIControlState) {
        colors[state] = color
        if state == .normal {
            backgroundColor = color
        }
    }

    // MARK: - overrides

    override var isEnabled: Bool {
        didSet { updateBackgroundColor() }
    }

    override var isHighlighted: Bool {
        didSet { updateBackgroundColor() }
    }

    // MARK: - color switching

    private lazy var colors: [UIControlState: UIColor] = [:]

    private func setBackgroundToState(_ state: UIControlState) {
        if let color = colors[state] {
            backgroundColor = color
        }
    }

    private func updateBackgroundColor() {
        if !isEnabled {
            setBackgroundToState(.disabled)
        } else if isHighlighted {
            setBackgroundToState(.highlighted)
        } else {
            setBackgroundToState(.normal)
        }
    }
}