objective-c - 如何在 NSViewController.transition 期间将 NSViewController 固定到 NSPopover 的顶部？

Question

我一直在尝试在 NSPopover 内创建从一个 subview Controller 到另一个 subview Controller 的滑动过渡。

我的问题是 subview Controller 在转换期间不会粘在 NSPopover 的顶部。它们从底部或顶部开始动画:

预期行为:两个 subview Controller 在转换期间都应粘在顶部，并且应简单地水平滑动。

这是我编写的用于触发转换的函数:

func loadViewController(_ childViewController: NSViewController, withTransition transitionOptions: NSViewController.TransitionOptions?) {
        addChild(childViewController)
        view.addSubview(childViewController.view)

        childViewController.view.layer?.borderColor = NSColor(calibratedRed: 0, green: 255, blue: 0, alpha: 1).cgColor
        childViewController.view.layer?.borderWidth = 2

        childViewController.view.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        view.layout()

        let oldViewController = currentViewController
        currentViewController = childViewController

        oldViewController?.view.layer?.borderColor = NSColor(calibratedRed: 255, green: 0, blue: 0, alpha: 1).cgColor
        oldViewController?.view.layer?.borderWidth = 2

        if let oldViewController = oldViewController  {
            transition(from: oldViewController, to: currentViewController!, options: transitionOptions ?? .slideLeft, completionHandler: { [weak oldViewController] in
                oldViewController?.removeFromParent()
                oldViewController?.view.removeFromSuperview()
            })
        }

        NSAnimationContext.runAnimationGroup({ (context) -> Void in
            context.duration = 0.5
            context.allowsImplicitAnimation = true

            self.parentPopover?.contentSize = NSSize(width: childViewController.preferredContentSize.width, height: childViewController.preferredContentSize.height)
        })
    }

知道是什么原因导致了这个问题吗？我尝试过处理 subview Controller 和父 View Controller 及其帧大小的约束。我就是不明白我做错了什么。

我已在此处上传了完整的可重现示例:https://github.com/maximilianschmitt/DebugPopoverAnimation

• MasterViewController.swift
• ChildViewController.swift

非常感谢您的帮助!

Answer 1

如果您期望如下面的动画所示

然后只需从动画 block 中删除内容大小的更新，如下所示

self.parentPopover?.contentSize = NSSize(width: childViewController.preferredContentSize.width, height: childViewController.preferredContentSize.height)
NSAnimationContext.runAnimationGroup({ (context) -> Void in
    context.duration = 0.5
    context.allowsImplicitAnimation = true

}) {
    oldViewController?.removeFromParent()
    oldViewController?.view.removeFromSuperview()
}

更新:保持弹出内容可动画(不需要进行上述更改)

对于这种情况，您唯一需要的是翻转弹出内容 View (这是 MasterViewController 的 View )的坐标系

class PopoverContentView: NSView {
    override var isFlipped: Bool { true }
}

class MasterViewController: NSViewController {
    ...
    override func loadView() {
        self.view = PopoverContentView()
    }