我已经阅读了很多关于保留周期的内容。必要时，父级UIViewController应始终对其子级strong具有UIViewController引用，而子级则应对其父级weak提及UIViewController。
仅当他们互相引用时才这样吗？例如，如果父级strong没有任何对其子级的引用，那么该子级是否可以对其父级UIViewController进行Task.cs引用？我能否解决这个问题，或者从长远的内存问题来看这是不好的做法？
答案 0 :(得分：3)
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。
UIViewController.h和
/*
If this view controller is a child of a containing view controller (e.g. a navigation controller or tab bar
controller,) this is the containing view controller. Note that as of 5.0 this no longer will return the
presenting view controller.
*/
weak public var parentViewController: UIViewController? { get }
您可以在此处看到，父母与子// An array of children view controllers. This array does not include any presented view controllers.
@available(iOS 5.0, *)
public var childViewControllers: [UIViewController] { get }
之间已经已经 strong和weak引用。您不应在从子级到父级的方向上添加任何新的ViewControllers引用，因为它可能导致内存泄漏。