import UIKit

class donghuaViewController: UIViewController {

    @IBOutlet weak var blue: UIView!

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view.

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    override func viewDidDisappear(animated: Bool) {

        UIView.animateWithDuration(1, animations: {

              self.blue.center.x=self.view.bounds.width - self.blue.center.x;

        })

    }

我这个有错吗？怎么不动？