cocoa - NSView 覆盖 NSPageController 在转换时消失

Question

我有一个 NSPageController，其中包含 8 个左右的 NSViewController。当鼠标位于窗口内部时，我希望有一个半透明的底部栏，并且无论鼠标在哪里，都有一个半透明的顶部栏。

我将顶部栏和底部栏添加到 View 中，以及 NSPageControllers viewDidLoad() 方法中的约束。

它们在第一页上显示得很好，但是当我开始从一个页面转换到另一个页面时，新的 NSViewController 会在覆盖的 View 上重新绘制，然后它们就会消失。我可以验证它们是否位于 NSViewControllers 下，因为然后我一直拖动到特定的一侧，我可以在下面看到它们。

有什么想法为什么会发生这种情况/我如何避免它？

代码:

class MyPageController: NSPageController {

    // MARK: - Properties
    fileprivate var mouseIsInside = false

    fileprivate var tabBar: TabBar!

    // MARK: - NSViewController
    override func viewDidLoad() {
        super.viewDidLoad()

        // add tab bar, then hide it (mouse in or outside of window will restore current state)
        tabBar = TabBar(frame: NSRect(x: 0, y:0, width: view.frame.size.width, height: 40))
        addTabBar(withAnimation: false)
        removeTabBar(withAnimation: false)

        NSLayoutConstraint.activate([
            tabBar.heightAnchor.constraint(equalToConstant: 40),
            tabBar.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            tabBar.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            tabBar.widthAnchor.constraint(equalTo: view.widthAnchor)
        ])

        delegate = self
        transitionStyle = .horizontalStrip
        arrangedObjects = ["0","1","2","3","4","5","6","7"]
        selectedIndex = 0
        view.wantsLayer = true

        // register for mouse events
        let trackingArea = NSTrackingArea(rect: view.bounds, options: [.mouseEnteredAndExited, .mouseMoved, .activeAlways, .inVisibleRect], owner: self, userInfo: nil)
        view.addTrackingArea(trackingArea)          
    }       
}

// NSPageController Delegate
extension PageController: NSPageControllerDelegate {

    func pageController(_ pageController: NSPageController, frameFor object: Any?) -> NSRect {
        return NSInsetRect(view.frame, -1, 0)
    }

    func pageController(_ pageController: NSPageController, identifierFor object: Any) -> String {      
        return (object as? String)!
    }

    func pageController(_ pageController: NSPageController, viewControllerForIdentifier identifier: String) -> NSViewController {           
        return ViewController(id: identifier)
    }

    func pageControllerWillStartLiveTransition(_ pageController: NSPageController) {
        Swift.print("pageControllerWillStartLiveTransition")
        addTabBar(withAnimation: false)
    }

    func pageControllerDidEndLiveTransition(_ pageController: NSPageController) {
        pageController.completeTransition()
        addTabBar(withAnimation: false)
        Swift.print("pageControllerWillEndLiveTransition")
    }
}    

// tabBar functions
extension PageController {
    func addTabBar(withAnimation shouldAnimate: Bool) {
        view.addSubview(tabBar)
        tabBar.frame.size.width = view.frame.size.width

        if mouseIsInside {              
            tabBar.showWithAnimation(shouldAnimate)             
        }
    }

    func removeTabBar(withAnimation shouldAnimate: Bool) {          
        tabBar.hideWithAnimation(shouldAnimate)         
    }    
}

// Mouse Movements
extension PageController {

    override func mouseEntered(with event: NSEvent) {
        mouseIsInside = true
        addTabBar(withAnimation: true)
    }

    override func mouseExited(with event: NSEvent) {
        mouseIsInside = false
        removeTabBar(withAnimation: true)
    }
}

提前致谢!

Answer 1

这似乎是一个 Unresolved 错误。这对我来说是固定的:

1. 如果 pageController 填满了窗口的 View ，则将 contentView 的背景设置为 nil。这样，我们看到的背景始终是 pageController 的背景。

2. 在此方法中对 View 进行排序:

   func pageControllerDidEndLiveTransition(_ pageController: NSPageController) {
       let controller = selectedViewController as! (YOUR_NSVIEWCONTROLLER_CLASS)
       controller.view.superview?.addSubview(controller.view, positioned: .below, relativeTo: TOOLBAR)
   }
   

将 YOUR_NSVIEWCONTROLLER_CLASS 替换为您的 ViewController 类名称，然后将 TOOLBAR 替换为您想要在顶部看到的 View 。