ButtonTestViewController.swift

import UIKit

class ButtonTestViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let btn = UIButton()
        let btnImg = UIImage(named:"image.png")
        btn.frame = CGRect(x:50,y:50,width:120,height:100)
        btn.setImage(btnImg, for: .normal)
        btn.addTarget(self, action: #selector(self.btnTapped(sender:)), for: .touchUpInside)
        self.view.addSubview(btn)
    }

    @objc func btnTapped(sender:UIButton){
        let rotationAnimation = CABasicAnimation(keyPath:"transform.rotation.z")
        rotationAnimation.toValue = CGFloat.pi * 2
        rotationAnimation.duration = 0.8
        rotationAnimation.repeatCount = 1
        sender.layer.add(rotationAnimation, forKey: "rotationAnimation")
    }

}