Interactive transition when presenting modally - ios

Question

I want to use interactive transitions in my app. I have two view controllers. And when user touches a button in first view controller I am presenting second view controller modally. My custom animation is working well but interactive transition is not working. I added a gesture to left edge of screen and when I pan from left edge second view controller is presenting but not interactive it is working as same as touching to button for presenting.
My class:
class MenuTransitionManager: UIPercentDrivenInteractiveTransition, UIViewControllerAnimatedTransitioning {
private var interactive = false
func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
return 2.5
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
let fromViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!
let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
let finalFrameForVC = transitionContext.finalFrameForViewController(toViewController)
let containerView = transitionContext.containerView()
let bounds = UIScreen.mainScreen().bounds
toViewController.view.frame = CGRectOffset(finalFrameForVC, 0, bounds.size.height)
containerView!.addSubview(toViewController.view)
UIView.animateWithDuration(transitionDuration(transitionContext), delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.0, options: .CurveLinear, animations: {
fromViewController.view.alpha = 0.5
toViewController.view.frame = finalFrameForVC
}, completion: {
finished in
transitionContext.completeTransition(true)
fromViewController.view.alpha = 1.0
})
}
func interactionControllerForPresentation(animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
// if our interactive flag is true, return the transition manager object
// otherwise return nil
return self.interactive ? self : nil
}
func interactionControllerForDismissal(animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
return self.interactive ? self : nil
}
private var enterPanGesture: UIScreenEdgePanGestureRecognizer!
var sourceViewController: UIViewController! {
didSet {
self.enterPanGesture = UIScreenEdgePanGestureRecognizer()
self.enterPanGesture.addTarget(self, action:"handleOnstagePan:")
self.enterPanGesture.edges = UIRectEdge.Left
self.sourceViewController.view.addGestureRecognizer(self.enterPanGesture)
}
}
func handleOnstagePan(pan: UIPanGestureRecognizer){
// how much distance have we panned in reference to the parent view?
let translation = pan.translationInView(pan.view!)
// do some math to translate this to a percentage based value
let d = translation.x / CGRectGetWidth(pan.view!.bounds) * 0.5
// now lets deal with different states that the gesture recognizer sends
switch (pan.state) {
case UIGestureRecognizerState.Began:
// set our interactive flag to true
self.interactive = true
// trigger the start of the transition
self.sourceViewController.performSegueWithIdentifier("showAction", sender: self)
break
case UIGestureRecognizerState.Changed:
// update progress of the transition
self.updateInteractiveTransition(d)
break
default: // .Ended, .Cancelled, .Failed ...
// return flag to false and finish the transition
self.interactive = false
self.finishInteractiveTransition()
}
}
}
My first view controller:
override func viewDidLoad() {
super.viewDidLoad()
self.transitionManager.sourceViewController = self
}
var transitionManager = MenuTransitionManager()
func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return transitionManager
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showAction" {
let toViewController = segue.destinationViewController as UIViewController
toViewController.transitioningDelegate = self
toViewController.modalPresentationStyle = .Custom
}
}
How can I fix it?

Answer 1

You also need to implement interactionControllerForPresentation(_:) on the view controller and vend an instance of UIViewControllerInteractiveTransitioning (which is a sub-protocol of UIPercentDrivenInteractiveTransition that your MenuTransitionManager class already implements).
The documentation around this subject is actually pretty good.