NSViewController，当在 Swift 下从 Storyboard实例化时，似乎在某处有一个引用循环。

多次调用下面的代码将实例化并设置一个新的 View Controller ，但旧的 View Controller 永远不会被释放。在代码中，containerViewController 是一个 NSViewController，它应该包含一个 NSViewController，containerView 是 containerViewController 中的 subview ，identifier 是要实例化的 Storyboard标识符。

// Remove any sub viewcontrollers and their views
for viewController in containerViewController.childViewControllers as [NSViewController] {
    viewController.view.removeFromSuperview()
    viewController.removeFromParentViewController()
}
// Create and set up the new view controller and view.
let viewController = storyboard!.instantiateControllerWithIdentifier(identifier) as NSViewController
let view = viewController.view
view.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(viewController.view)
containerViewController.addChildViewController(viewController)
containerView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[view]|", options: nil, metrics: nil, views: ["view": view]))
containerView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[view]|", options: nil, metrics: nil, views: ["view": view]))

(示例项目不再可用)

我使用了 Apple TSI，他们认为这是一个错误，我已将其提交，但我希望其他人会反对这个问题，因为现在看到 NSViewControllers 和 Storyboard现在是 OSX 上的事实。你是如何解决这个问题的？还是它不会影响其他任何人而我做错了什么？

赏金前编辑:每个 View Controller 必须能够从代码链接到任何其他 View Controller ，因为目标是动态确定的。这似乎可以删除 segues。

错误修复

从 Xcode 6.3 开始，这不再是错误。

最佳答案

另一个答案。

似乎只有定义在 Storyboard 上的 segues 才能执行 View Controller 释放。 因此，这是一个非常丑陋但可行的解决方法。

class DismissSegue: NSStoryboardSegue {

    var nextViewControllerIdentifier:String?

    override func perform() {
        let src = self.sourceController as NSViewController
        let windowController = src.view.window!.windowController() as TopLevelWindowController

        src.view.removeFromSuperview()
        src.removeFromParentViewController()

        if let identifier = nextViewControllerIdentifier {
            windowController.setNewViewController(identifier)
        }
    }
}

class TopLevelWindowController: NSWindowController {

    var containerView: NSView!
    var containerViewController: ContainerViewController! {
        didSet {
            setNewViewController("FirstView")
        }
    }

    func setNewViewController(identifier: String) {
        // Create and set up the new view controller and view.
        let viewController = storyboard!.instantiateControllerWithIdentifier(identifier) as NSViewController
        let view = viewController.view
        view.translatesAutoresizingMaskIntoConstraints = false
        containerView.addSubview(viewController.view)
        containerViewController.addChildViewController(viewController)
        containerView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[view]|", options: nil, metrics: nil, views: ["view": view]))
        containerView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[view]|", options: nil, metrics: nil, views: ["view": view]))
    }
}

class ContainerViewController: NSViewController {

    @IBOutlet var containerView: NSView!

    override func viewDidAppear() {
        super.viewDidAppear()
        if let window = view.window {
            if let topLevelWindowController = window.windowController() as? TopLevelWindowController {
                topLevelWindowController.containerView = containerView
                topLevelWindowController.containerViewController = self
            }
        }
    }

}

class FirstViewController: NSViewController {

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        let pointerAddress = NSString(format: "%p", unsafeBitCast(self, Int.self))
        NSLog("First VC init at \(pointerAddress)")
    }

    deinit {
        let pointerAddress = NSString(format: "%p", unsafeBitCast(self, Int.self))
        NSLog("First VC de-init at \(pointerAddress)")
    }

    override func prepareForSegue(segue: NSStoryboardSegue, sender: AnyObject?) {
        if let segue = segue as? DismissSegue {
            segue.nextViewControllerIdentifier = "SecondView"
        }
    }
}

class SecondViewController: NSViewController {

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        let pointerAddress = NSString(format: "%p", unsafeBitCast(self, Int.self))
        NSLog("Second VC init at \(pointerAddress)")
    }

    deinit {
        let pointerAddress = NSString(format: "%p", unsafeBitCast(self, Int.self))
        NSLog("Second VC de-init at \(pointerAddress)")
    }

    override func prepareForSegue(segue: NSStoryboardSegue, sender: AnyObject?) {
        if let segue = segue as? DismissSegue {
            segue.nextViewControllerIdentifier = "FirstView"
        }
    }
}

修改 Storyboard 的过程:

1. 断开 @IBAction 与按钮的连接。
2. 使用普通 NSViewController 创建“DUMMY” View Controller 场景。
3. 将自定义 segues 从按钮连接到“DUMMY”。
4. 如图所示配置这些 segue。

如果此解决方案不能满足您的需求，请告诉我。

关于macos - 带有 Storyboard的 NSViewController 引用循环，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26836515/