import UIKit

class ViewController: UIViewController {

@IBOutlet weak var stackOutlet: UIStackView!
@IBOutlet weak var buttonOutlet: UIButton!
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func buttonAction(_ sender: AnyObject) {

    let newView = UIView(frame: CGRect(x: 0, y: 0, width: 240, height: 128))

    newView.backgroundColor = UIColor.green
    self.stackOutlet.insertArrangedSubview(newView, at: 1)

    UIView.animate(withDuration: 0.5, delay: 0, options: .curveEaseInOut, animations: {
        newView.heightAnchor.constraint(equalToConstant: 128).isActive = true
        newView.widthAnchor.constraint(equalToConstant: 240).isActive = true
        self.view.layoutIfNeeded()
        }, completion:
        { finished in
        print("OKKK")
        })
    print(stackOutlet.subviews.count)

}

}