didPanView.swift

@objc func didPanView(sender: UIPanGestureRecognizer) {
    let viewToMove = sender.view!
    view.bringSubview(toFront: viewToMove)
    let translation = sender.translation(in: view)
    let newCenter = CGPoint(x: viewToMove.center.x + translation.x, y: viewToMove.center.y + translation.y)
    viewToMove.center = newCenter
    sender.setTranslation(CGPoint.zero, in: view)
}