UIView.animate( withDuration: duration, delay: 0.0, options: .curveEaseInOut, animations: { self.alpha = 0.0 }, completion: { _ in self.isHidden = true } ) 本当はこうしたいUIView.animate( withDuration: duration, delay: 0.0, options: .curveEaseInOut, animations: { self.alpha = 0.0 }, completion: { _ in self.isHidden = true } ) 本当はこうしたい