import UIKit
import StoreKit

class ViewController: UIViewController {
    
    @IBAction func button(_ sender: Any) {
        self.openStoreProductWithiTunesItemIdentifier(identifier: "")
    }
    override func viewDidLoad() {
        super.viewDidLoad()
    }

}

extension UIViewController: SKStoreProductViewControllerDelegate {
    func openStoreProductWithiTunesItemIdentifier(identifier: String) {
        let storeViewController = SKStoreProductViewController()
        storeViewController.delegate = self
        
        let otherVC = UIViewController()
        otherVC.view.backgroundColor = .blue
        otherVC.modalTransitionStyle = .crossDissolve
        
        let parameters = [ SKStoreProductParameterITunesItemIdentifier : "1326479187"]
        storeViewController.modalTransitionStyle = .crossDissolve
        self.present(storeViewController, animated: true, completion: {storeViewController.modalTransitionStyle = .crossDissolve})
        
        storeViewController.loadProduct(withParameters: parameters) { [weak self] (loaded, error) -> Void in
//            self?.present(storeViewController, animated: false, completion: {storeViewController.modalTransitionStyle = .crossDissolve})
        }
    }
    
    public func productViewControllerDidFinish(_ viewController: SKStoreProductViewController) {
        viewController.dismiss(animated: true, completion: nil)
    }
}