How to animate display of same View Controller but with updated content - swift4

Question

I want to animate an update to a sceen's content as if transitioning to a different View Controller. For example, imagine a scene of a calendar page with today's events. A swipe to the left updates the content to tomorrow's events but the View Controller and scene are the same. Still, I'd like to animate the new content sliding in from the right.
I've tried animating moving the entire view to the left. And that works, but it reveals a black screen beneath, which although quickly replaced with the correct content is nevertheless jarring.
I remember back in the HyperCard days you could lock the display of a card, update the contents, then unlock the display with a transition, say, a dissolve or wipe. I understand that is probably not how iOS does things, but I mention it just to help describe what I'm trying to do.
Adding code that does gesture recognition and move...
#objc func swipeDetected(gesture: UIGestureRecognizer) {
let calendar = Calendar.current
if let swipeGesture = gesture as? UISwipeGestureRecognizer {
switch swipeGesture.direction {
case .left:
// move current page to the left
animateViewMoving(right: false, timeInterval: 0.3)
// update content
currentDate = calendar.date(byAdding: .day, value: 1, to: currentDate)!
populateSchedItems()
self.tableView.reloadData()
// return page with no duration
animateViewMoving(right: true, timeInterval: 0.0)
case .right:
// move page to left with no duration
animateViewMoving(right: false, timeInterval: 0.0)
// update content
currentDate = calendar.date(byAdding: .day, value: -1, to: currentDate)!
populateSchedItems()
self.tableView.reloadData()
// slide new content in from the left
animateViewMoving(right: true, timeInterval: 0.3)
default:
break
}
}
}
func animateViewMoving (toTheRight: Bool, timeInterval: Double) {
let frameWidth = self.view.frame.width
let movementDuration:TimeInterval = timeInterval
let movement:CGFloat = ( toTheRight ? frameWidth : -frameWidth)
UIView.beginAnimations( "animateView", context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(movementDuration )
self.view.frame = self.view.frame.offsetBy(dx: movement, dy: 0)
UIView.commitAnimations()
}

Answer 1

Take a snapshot view of the current contents and place it behind the current view. (This will give us something other than the black window to look at behind the animation.) Now do exactly what you're already doing: move the real view off to the side and animate it in. Now quietly remove the snapshot view.