在Github中制作了一个演示项目
https://github.com/rishi420/SwipeRightToPopController

我用过UIViewControllerAnimatedTransitioning协议

从文档中：

//这用于百分比驱动的交互式过渡以及容器控制器…

UIPanGestureRecognizer在控制器的视图中添加了一个。这是手势的动作：

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
    }
}

脚步：

1. 计算视图上的拖动百分比
2. .Begin:指定要执行的序列并分配UINavigationController委托。需要代表InteractiveTransitioning
3. .Changed: 带百分比的UpdateInteractiveTransition
4. .Ended: 如果拖动50％或更高或更高的速度，则继续保持过渡状态，否则取消
5. .Cancelled, .Failed: 取消过渡

参考文献：

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