如何在Swift 3.0中拖放精灵？

我有一个实现，其中我将UIImageView子类化，并将其称为“ DraggableImage”

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {        originalPosition = self.center    }override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {        if let touch = touches.first { let position = touch.location(in: self.superview) self.center = CGPoint(x: position.x, y: position.y)        }    }override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {        self.center = originalPosition    }