slideAnimation.swift

class SlidePushAnimation: NSObject, UIViewControllerAnimatedTransitioning {
    //1
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.5
    }
    //2
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        //3
        guard let toViewController = transitionContext.viewController(forKey: .to), let fromViewController = transitionContext.view(forKey: .from) else {return}
        //4
        let window = UIScreen.main.bounds
        //5
        transitionContext.containerView.addSubview(toViewController.view)
        //5
        toViewController.view.transform = .init(translationX: window.size.width, y: 1)
        //6
        let duration = self.transitionDuration(using: transitionContext)
        //7
        UIView.animate(withDuration: duration, animations: {
            toViewController.view.transform = .identity
            fromViewController.transform = .init(translationX: (-window.size.width), y: 1)
        }, completion: { _ in
        //8
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        })
    }
    
}