Кнопка, которая меняет цвет фона в момент нажатия

ColoredButton.swift

import UIKit

class ColorButton: UIButton {
    
    let normalColor = UIColor.blue
    let pressedColor = UIColor.green

    override func awakeFromNib() {
        super.awakeFromNib()
        
        let normalBg = coloredImage(normalColor)
        let pressedBg = coloredImage(pressedColor)
        
        setBackgroundImage(normalBg, for: .normal)
        setBackgroundImage(pressedBg, for: .selected)
        setBackgroundImage(pressedBg, for: .highlighted)
        
    }
    
    private func coloredImage(_ color: UIColor) -> UIImage {
        let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
        
        UIGraphicsBeginImageContext(rect.size)
        
        let context = UIGraphicsGetCurrentContext()
        context!.setFillColor(color.cgColor)
        context!.fill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        
        UIGraphicsEndImageContext()
        return image!
    }

}