Custom View Transition without use of Storyboard segues (Swift) - ios

Question

I have two views I would like to make a swipe style transition accross and I have done that when there is a segue to act on but the I don't have one here so am not sure how to apply my animation class. All I have in my class is:
let stb = UIStoryboard(name: "Walkthrough", bundle: nil)
let walkthrough = stb.instantiateViewControllerWithIdentifier("walk") as! BWWalkthroughViewController
self.presentViewController(walkthrough, animated: true, completion: nil)
I want to apply apply the following custom segue:
class CustomSegue: UIStoryboardSegue {
override func perform() {
// Assign the source and destination views to local variables.
var firstVCView = self.sourceViewController.view as UIView!
var secondVCView = self.destinationViewController.view as UIView!
// Get the screen width and height.
let screenWidth = UIScreen.mainScreen().bounds.size.width
let screenHeight = UIScreen.mainScreen().bounds.size.height
// Specify the initial position of the destination view.
secondVCView.frame = CGRectMake(0.0, screenHeight, screenWidth, screenHeight)
// Access the app's key window and insert the destination view above the current (source) one.
let window = UIApplication.sharedApplication().keyWindow
window?.insertSubview(secondVCView, aboveSubview: firstVCView)
// Animate the transition.
UIView.animateWithDuration(0.2, animations: { () -> Void in
firstVCView.frame = CGRectOffset(firstVCView.frame, -screenWidth, 0.0)
secondVCView.frame = CGRectOffset(secondVCView.frame, -screenWidth, 0.0)
}) { (Finished) -> Void in
self.sourceViewController.presentViewController(self.destinationViewController as! UIViewController,
animated: false,
completion:nil)
}
}
}
I cannot get it to work any pointers please?

Answer 1

While the first answer should be "use Storyboard Segues", you can solve custom transitions this way:
Generic Approach
Modify your CustomSegue to adopt both UIStoryboardSegue and UIViewControllerAnimatedTransitioning protocols.
Refactor CustomSegue so that the animation can be used by both protocols.
Setup a delegate to the navigation controller, which can be itself, to supply the custom transitions to push & pop
let animationControllerForOperation create and return an instance of CustomSegue, with an identifier of your choice.
Overview
// Adopt both protocols
class CustomSegue: UIStoryboardSegue, UIViewControllerAnimatedTransitioning {
func animate(firstVCView:UIView,
secondVCView:UIView,
containerView:UIView,
transitionContext: UIViewControllerContextTransitioning?) {
// factored transition code goes here
}) { (Finished) -> Void in
if let context = transitionContext {
// UIViewControllerAnimatedTransitioning
} else {
// UIStoryboardSegue
}
}
}
func transitionDuration(transitionContext: UIViewControllerContextTransitioning) -> NSTimeInterval {
// return timing
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
// Perform animate using transitionContext information
// (UIViewControllerAnimatedTransitioning)
}
override func perform() {
// Perform animate using segue (self) variables
// (UIStoryboardSegue)
}
}
Below is the complete code example. It has been tested. Notice that I also fixed a few animation bugs from the original question, and added a fade-in effect to emphasize the animation.
CustomSegue Class
// Animation for both a Segue and a Transition
class CustomSegue: UIStoryboardSegue, UIViewControllerAnimatedTransitioning {
func animate(firstVCView:UIView,
secondVCView:UIView,
containerView:UIView,
transitionContext: UIViewControllerContextTransitioning?) {
// Get the screen width and height.
let offset = secondVCView.bounds.width
// Specify the initial position of the destination view.
secondVCView.frame = CGRectOffset(secondVCView.frame, offset, 0.0)
firstVCView.superview!.addSubview(secondVCView)
secondVCView.alpha = 0;
// Animate the transition.
UIView.animateWithDuration(self.transitionDuration(transitionContext!),
animations: { () -> Void in
firstVCView.frame = CGRectOffset(firstVCView.frame, -offset, 0.0)
secondVCView.frame = CGRectOffset(secondVCView.frame, -offset, 0.0)
secondVCView.alpha = 1; // emphasis
}) { (Finished) -> Void in
if let context = transitionContext {
context.completeTransition(!context.transitionWasCancelled())
} else {
self.sourceViewController.presentViewController(
self.destinationViewController as! UIViewController,
animated: false,
completion:nil)
}
}
}
func transitionDuration(transitionContext: UIViewControllerContextTransitioning) -> NSTimeInterval {
return 4 // four seconds
}
// Perform Transition (UIViewControllerAnimatedTransitioning)
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
self.animate(transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!.view,
secondVCView: transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!.view,
containerView: transitionContext.containerView(),
transitionContext: transitionContext)
}
// Perform Segue (UIStoryboardSegue)
override func perform() {
self.animate(self.sourceViewController.view!!,
secondVCView: self.destinationViewController.view!!,
containerView: self.sourceViewController.view!!.superview!,
transitionContext:nil)
}
}
Host ViewController Class
class ViewController: UIViewController, UINavigationControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.navigationController?.delegate = self
}
func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
switch operation {
case .Push:
return CustomSegue(identifier: "Abc", source: fromVC, destination: toVC)
default:
return nil
}
}
}