swift-button.swift

import Foundation
import UIKit

public class ProductTable : UIView {
    
    open var quantity : NSNumber = 0 {
        didSet {
            updateLabel()
        }
    }
    
    var Label: UILabel!
    var Button: UIButton!
    
    override init(frame: CGRect){
        super.init(frame: frame)

        Label = UILabel(frame: CGRect(x: 0, y: 0, width: 400,
                                          height: 50))
        Button = UIButton(frame: CGRect(x: 0, y: 55, width: 400, height: 50))
        
        Button.backgroundColor = UIColor.blue
        Button.setTitle("Increase quantity on the Swift side", for: .normal)
        Button.setTitleColor(UIColor.white, for: .normal)
        Button.addTarget(self, action: #selector(ProductTable.onClick), for: .touchUpInside)

        updateLabel()
        
        self.addSubview(Label)
        self.addSubview(Button)
    }
    
    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
    
    public func updateLabel() {
        let number = String(quantity as! Int)
        
        Label.text = "On the Swift side, quantity is now: " + number
    }
    
    func onClick() {
        NSLog("onClick")
    }
}