How do you present a UIViewController from the top of the screen instead of the bottom?

Question

I am using a UIViewController and I use presentModalViewController:controllerr animated:YES to present it but I would like if it would slide down from the top of the screen

Answer 1

public extension UINavigationController {

    func pushViewControllerFromTop(viewController vc: UIViewController) {
        vc.view.alpha = 0
        self.present(vc, animated: false) { () -> Void in
            vc.view.frame = CGRect(x: 0, y: -vc.view.frame.height, width: vc.view.frame.width, height: vc.view.frame.height)
            vc.view.alpha = 1
            UIView.animate(withDuration: 1, 
                           animations: { () -> Void in
                               vc.view.frame = CGRect(x: 0, y: 0, width: vc.view.frame.width, height: vc.view.frame.height)
                           }, 
                           completion: nil)
        }
    }

    func dismissViewControllerToTop() {
        if let vc = self.presentedViewController {
            UIView.animate(withDuration: 1, 
                           animations: { () -> Void in
                               vc.view.frame = CGRect(x: 0, y: -vc.view.frame.height, width: vc.view.frame.width, height: vc.view.frame.height)
                           }, 
                           completion: { complete -> Void in
                               if complete {
                                   self.dismiss(animated: false, completion: nil)
                               }
                           })
        }
    }
}