当在ARC下取消分配视图控制器时，如果另一个对象具有强引用，是否还会取消分配其属性? [英] When a view controller is dealloc'd under ARC, are it's properties also dealloc'd if another object has a strong reference?

问题描述

我有一个地图应用程序，它使用外围滑入/滑出右视图控制器，就像下面显示的G​​oogle Maps应用程序(

I have a mapping application that uses a peripheral slide in/slide out right hand view controller, much like the Google Maps application shown below (source):

在我的应用中，此滑出视图具有weak delegate属性，我将地图视图控制器设置为委托(例如，在myMapViewController内部的mapOptionsViewController.delegate = self).我也希望使用右手幻灯片查看其他类型的信息.例如.在地图上显示用户选择的餐厅菜单menuViewController.

In my app, this slide out view has a weak delegate property, and I set the map view controller to be the delegate (e.g. mapOptionsViewController.delegate = self from inside myMapViewController). I also wish to use the right hand slide in view for other sorts of information though. E.g. displaying a menu for a restaurant that a user selects on the map, menuViewController.

我的问题是，如果我将mapOptionsViewController换成menuViewController，是否还需要从myMapViewController手动nil出mapOptionsViewController.delegate吗?我担心的是，即使在我切换到menuViewController时对mapOptionsViewController进行了分配/处置，由于myMapViewController仍指向旧的mapOptionsViewController.delegate，所以mapOptionsViewController.delegate的内存将不会被释放堆.

My question is, if I swap out mapOptionsViewController for menuViewController, do I need to manually nil out the mapOptionsViewController.delegate from myMapViewController also? My concern is that even if mapOptionsViewController is dealloc'd/disposed of when I do the switch to menuViewController, because myMapViewController still points to the old mapOptionsViewController.delegate, mapOptionsViewController.delegate's memory will not be released from the heap.

因此，基本上，如果您有一个对象视图控制器foo(我的地图)，它是另一个视图控制器bar(地图选项)的委托，例如bar.delegate = foo，那么您将bar对于baz(餐厅菜单)，我是否需要从foo设置bar.delegate = nil.或者，当包含视图控制器delegate时bar取消delegate会由于被baz替换而被取消分配?

So basically, if you have an object view controller foo (my map) which is the delegate for another view controller bar (map options), such that bar.delegate = foo, and then you switch out bar for baz (restaurant menu), do I need to set bar.delegate = nil from foo. Or, will bar nil out delegate when the view controller delegate is contained in is dealloc'd as a result of being replaced with baz?

推荐答案

总之，没有.只要一个对象仍然具有强引用，并且最后一个具有字符串引用的对象没有被释放，它就不会被释放.或者，您有一个错误.

In one word, no. as long as an object still have strong reference, and the last object that have a string reference to it is not deallocated, it is not deallocated. Or, you have a bug.

此外，当weak引用的对象被释放时，该引用将自动清零.但是assign不会.

Also, weak references will be automatically zeroed when the object referencing to it is deallocated. However assign ones will not.

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