How can I implement "drag right to dismiss" a View Controller that's in a navigation stack?

Question

By default, if you drag right from the left edge of the screen, it will drag away the ViewController and take it off the stack.

I want to extend this functionality to the entire screen. When the user drags right anywhere, I'd like the same to happen.

I know that I can implement a swipe right gesture and simply call self.navigationController?.popViewControllerAnimated(true)

However, there is no "dragging" motion. I want the user to be able to right-drag the view controller as if it's an object, revealing what's underneath. And, if it's dragged past 50%, dismiss it. (Check out instagram to see what I mean.)

Answer 1

Made a demo project in Github
https://github.com/rishi420/SwipeRightToPopController

I've used UIViewControllerAnimatedTransitioning protocol

From the doc:

// This is used for percent driven interactive transitions, as well as for container controllers ...

Added a UIPanGestureRecognizer to the controller's view. This is the action of the gesture:

func handlePanGesture(panGesture: UIPanGestureRecognizer) {      let percent = max(panGesture.translationInView(view).x, 0) / view.frame.width      switch panGesture.state {      case .Began:         navigationController?.delegate = self         navigationController?.popViewControllerAnimated(true)      case .Changed:         percentDrivenInteractiveTransition.updateInteractiveTransition(percent)      case .Ended:         let velocity = panGesture.velocityInView(view).x          // Continue if drag more than 50% of screen width or velocity is higher than 1000         if percent > 0.5 || velocity > 1000 {             percentDrivenInteractiveTransition.finishInteractiveTransition()         } else {             percentDrivenInteractiveTransition.cancelInteractiveTransition()         }      case .Cancelled, .Failed:         percentDrivenInteractiveTransition.cancelInteractiveTransition()      default:         break     } } 

Steps:

1. Calculate the percentage of drag on the view
2. .Begin: Specify which segue to perform and assign UINavigationController delegate. delegate will be needed for InteractiveTransitioning
3. .Changed: UpdateInteractiveTransition with percentage
4. .Ended: Continue remaining transitioning if drag 50% or more or higher velocity else cancel
5. .Cancelled, .Failed: cancel transitioning

References:

1. UIPercentDrivenInteractiveTransition
2. https://github.com/visnup/swipe-left
3. https://github.com/robertmryan/ScreenEdgeGestureNavigationController
4. https://github.com/groomsy/custom-navigation-animation-transition-demo