ios - 使用 UIPanGestureRecognizer 在 Swift 中进行左侧导航

Question

我正在使用 Raywenderlich 教程实现没有库的导航:

http://www.raywenderlich.com/78568/create-slide-out-navigation-panel-swift

我尝试对代码进行一些修改，使其没有右侧导航，但是当我滑动时，我得到了一个黑色背景，它正在打开。

所以我认为问题可能来自 UIPanGestureRecognizer 并尝试使用 UISwipeGestureRecognizer 但我不知道该怎么做或者它是否是好方法:

enum SlideOutState{
    case BothCollapsed
    case LeftPanelExpanded
}

class ContainerViewController: UIViewController {

    var centerNavigationController: UINavigationController!
    var centerViewController: CenterViewController!
    var currentState: SlideOutState = .BothCollapsed
    var leftViewController: SidePanelViewController?
    let centerPanelExpandedOffset: CGFloat = 60

    override func viewDidLoad() {
        super.viewDidLoad()

        centerViewController = UIStoryboard.centerViewController()
        centerViewController.delegate = self

        centerNavigationController = UINavigationController(rootViewController: centerViewController)
        view.addSubview(centerNavigationController.view)
        addChildViewController(centerNavigationController)

        centerNavigationController.didMoveToParentViewController(self)

        /*
        let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: "handlePanGesture:")
        centerNavigationController.view.addGestureRecognizer(panGestureRecognizer)
        */

        var swipeRight = UISwipeGestureRecognizer(target: self, action: "handleSwipeGesture:")
        swipeRight.direction = UISwipeGestureRecognizerDirection.Right
        self.view.addGestureRecognizer(swipeRight)
    }
}

// MARK: CenterViewController delegate


extension ContainerViewController : CenterViewControllerDelegate{

    func toggleLeftPanel() {
        let notAlreadyExpanded = (currentState != .LeftPanelExpanded)

        if notAlreadyExpanded {
            addLeftPanelViewController()
        }

        animateLeftPanel(shouldExpand: notAlreadyExpanded)
    }

    func collapseSidePannels() {
        switch (currentState) {
        case .LeftPanelExpanded:
            toggleLeftPanel()
        default:
            break
        }
    }

    func addLeftPanelViewController() {
        if (leftViewController == nil) {
            leftViewController = UIStoryboard.leftViewController()
            leftViewController!.menus = Menu.allMenu()

            addChildSidePanelController(leftViewController!)
        }
    }

    func addChildSidePanelController(sidePanelController: SidePanelViewController) {
        sidePanelController.delegate = centerViewController
        view.insertSubview(sidePanelController.view, atIndex: 0)

        addChildViewController(sidePanelController)
        sidePanelController.didMoveToParentViewController(self)
    }


    func animateLeftPanel(#shouldExpand: Bool) {
        if (shouldExpand) {
            currentState = .LeftPanelExpanded

            animateCenterPanelXPosition(targetPosition: CGRectGetWidth(centerNavigationController.view.frame) - centerPanelExpandedOffset)
        } else {
            animateCenterPanelXPosition(targetPosition: 0) { finished in
                self.currentState = .BothCollapsed

                self.leftViewController!.view.removeFromSuperview()
                self.leftViewController = nil;
            }
        }
    }

    func animateCenterPanelXPosition(#targetPosition: CGFloat, completion: ((Bool) -> Void)! = nil) {
        UIView.animateWithDuration(0.5, delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0, options: .CurveEaseInOut, animations: {
            self.centerNavigationController.view.frame.origin.x = targetPosition
            }, completion: completion)
    }

}

/*
extension ContainerViewController: UIGestureRecognizerDelegate {
    // MARK: Gesture recognizer

    func handlePanGesture(recognizer: UIPanGestureRecognizer) {
        let gestureIsDraggingFromLeftToRight = (recognizer.velocityInView(view).x > 0)

        switch(recognizer.state) {
        case .Began:
            if (currentState == .BothCollapsed) {
                if (gestureIsDraggingFromLeftToRight) {
                    addLeftPanelViewController()
                }
            }
        case .Changed:
            recognizer.view!.center.x = recognizer.view!.center.x + recognizer.translationInView(view).x
        case .Ended:
            if (leftViewController != nil) {
                // animate the side panel open or closed based on whether the view has moved more or less than halfway
                let hasMovedGreaterThanHalfway = recognizer.view!.center.x > view.bounds.size.width
                animateLeftPanel(shouldExpand: hasMovedGreaterThanHalfway)
            }
        default:
            break
        }
    }
}
*/

extension ContainerViewController: UIGestureRecognizerDelegate {
    func handleSwipeGesture(gesture: UIGestureRecognizer) {
        if let swipeGesture = gesture as? UISwipeGestureRecognizer{
            switch (gesture.state){
            case UISwipeGestureRecognizerDirection.Right:
                addLeftPanelViewController()
            default:
                break
            }
        }
    }
}

private extension UIStoryboard {
    class func mainStoryboard() -> UIStoryboard { return UIStoryboard(name: "Main", bundle: NSBundle.mainBundle()) }

    class func leftViewController() -> SidePanelViewController? {
        return mainStoryboard().instantiateViewControllerWithIdentifier("LeftViewController") as? SidePanelViewController
    }

    class func centerViewController() -> CenterViewController? {
        return mainStoryboard().instantiateViewControllerWithIdentifier("CenterViewController") as? CenterViewController
    }

}

Answer 1

只需更改 .Changed 大小写:

if (((recognizer.view!.center.x + recognizer.translationInView(view).x) > view.center.x || gestureIsDraggingFromLeftToRight) && (recognizer.view!.center.x >= view.center.x && recognizer.velocityInView(view).x > 0 || recognizer.view!.center.x > view.center.x && recognizer.velocityInView(view).x < 0) && recognizer.view!.center.x + recognizer.translationInView(view).x > view.center.x) {
recognizer.view!.center.x = recognizer.view!.center.x + recognizer.translationInView(view).x
                recognizer.setTranslation(CGPointZero, inView: view)
}