AutoLayout面试题记录-用NSLayoutConstraint写动画

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var topY: NSLayoutConstraint!
    @IBOutlet weak var destinationBtn: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

    }

    @IBAction func click(_ sender: UIButton) {

        UIView.animate(withDuration: , delay: , options: UIViewAnimationOptions.curveEaseInOut, animations: {
            self.topY.constant =
            self.view.layoutIfNeeded()
        }) { (true) in

        }

    }

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

}

storyboard中2个按钮，一个点击，一个移动动画用的