RatingComponent.swift

@IBDesignable
class RatingComponent: UIControl {
    @IBInspectable
    var count: Int = 5 {
        didSet {
            ratings = []
            for i in 0..<count {
                let button = UIButton(type: .custom)
                button.setImage(selectedImage, for: .selected)
                button.setImage(unSelectedImage, for: .normal)
                button.imageView?.contentMode = .scaleAspectFit
                button.isSelected = i <= (value-1)
                button.tag = i
                button.addTarget(self, action: #selector(onTapRating(_:)), for: .touchUpInside)
                ratings.append(button)
                verticalStack.addArrangedSubview(button)
            }
        }
    }
    
    @IBInspectable
    var selectedImage: UIImage? = nil {
        didSet {
            for rating in ratings {
                rating.setImage(selectedImage, for: .selected)
            }
        }
    }
    
    @IBInspectable
    var unSelectedImage: UIImage? = nil {
        didSet {
            for rating in ratings {
                rating.setImage(unSelectedImage, for: .normal)
            }
        }
    }
    
    @IBInspectable
    var value: Int = 0 {
        didSet {
            for rating in ratings {
                rating.isSelected = rating.tag <= (value-1)
            }
        }
    }
    
    private var ratings: [UIButton] = []
    
    private var verticalStack: UIStackView = {
        let stack = UIStackView()
        stack.axis = .horizontal
        stack.distribution = .fillEqually
        stack.spacing = 8
        stack.translatesAutoresizingMaskIntoConstraints = false
        return stack
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
    
    override func prepareForInterfaceBuilder() {
        setup()
    }
    
    private func setup() {
        if !subviews.contains(verticalStack) {
            addSubview(verticalStack)
            verticalStack.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
            verticalStack.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
            verticalStack.topAnchor.constraint(equalTo: topAnchor).isActive = true
            verticalStack.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
        }
    }
    
    @objc
    private func onTapRating(_ sender: UIButton) {
        if isEnabled {
            value = sender.tag + 1
            sendActions(for: .valueChanged)
        }
    }
}