var testViewLeadingConstraint: NSLayoutConstraint! @IBAction func buttonTouchDown(_ sender: Any) { self.testViewLeadingConstraint.constant = self.testView.frame.width UIView.animate(withDuration: 3.0, animations: { self.view.layoutIfNeeded() }) } } ->΄ͱΜͲͷαΠτͰಉ͡༰͕ग़ͯ͘Δ