UISearchDisplayController在viewDidUnload之后导致崩溃 [英] UISearchDisplayController causes crash after viewDidUnload
问题描述
我有一个项目使用StoryBoards和 UISearchDisplayController 在 UINavigationController 的上下文中使用，它出现在根目录中视图 - 控制。当我将一个新的视图控制器推入堆栈并导致模拟内存警告（或实际上得到一个低内存警告）。上一个视图控制器成功卸载其视图。但是，当我从堆栈弹出第二个视图控制器时，我得到一个 EXC_BAD_ACCESS 。我打开了NSZombies并发现了这个：
I have a project using StoryBoards and UISearchDisplayController used in the context of a UINavigationController, that appears in the root viewcontroller. When I push a new view controller onto the stack and I cause a simulated memory warning (or actually get a low memory warning). The previous view controller successfully unloads its view. However, when I pop the second view controller off of the stack I get an EXC_BAD_ACCESS. I turned on NSZombies and discovered this:
[UISearchDisplayController retain]：发送到解除分配的实例的消息0xb13aa30
[UISearchDisplayController retain]: message sent to deallocated instance 0xb13aa30
我不是（至少在我的代码中）将该消息发送到 UISearchDisplayController 。用编程方式来说，我没有做任何事情。断点显示我甚至没有进入第一个视图控制器的 viewDidLoad 。
I am not (at least in my code) sending that message to the UISearchDisplayController. I am not doing anything, programmatically speaking, with it. Break points reveal that I am not even making it into the viewDidLoad of the first view controller.
好奇的东西，虽然：对于笑声和咯咯笑声，我决定在我的 viewDidLoad 中直接保留 SDC，只是为了看看会发生什么，没有发生崩溃。但是，我的 UISearchDisplayController 实例是 nil 。
Something curious, though: for laughs and giggles I decided to outright retain the SDC in my viewDidLoad, just to see what would happen and no crash occurs. However, my UISearchDisplayController instance is nil.
I做了一个回溯并获得了这个输出：
I did a backtrace and get this output:
#0 0x01e30e1e in ___forwarding___ ()
#1 0x01e30ce2 in __forwarding_prep_0___ ()
#2 0x01dd1490 in CFRetain ()
#3 0x01eb69c0 in +[__NSArrayI __new::] ()
#4 0x01e0a00a in -[__NSPlaceholderArray initWithObjects:count:] ()
#5 0x01e34f52 in +[NSArray arrayWithObjects:count:] ()
#6 0x01e5e084 in -[NSDictionary allValues] ()
#7 0x01035272 in -[UINib instantiateWithOwner:options:] ()
#8 0x00edce2c in -[UIViewController _loadViewFromNibNamed:bundle:] ()
#9 0x00edd3a9 in -[UIViewController loadView] ()
#10 0x00edd5cb in -[UIViewController view] ()
#11 0x00edd941 in -[UIViewController contentScrollView] ()
#12 0x00eef47d in -[UINavigationController _computeAndApplyScrollContentInsetDeltaForViewController:] ()
#13 0x00eef66f in -[UINavigationController _layoutViewController:] ()
#14 0x00eef93b in -[UINavigationController _startTransition:fromViewController:toViewController:] ()
#15 0x00ef03df in -[UINavigationController _startDeferredTransitionIfNeeded] ()
#16 0x00ef16cb in _popViewControllerNormal ()
#17 0x00ef196c in -[UINavigationController _popViewControllerWithTransition:allowPoppingLast:] ()
#18 0x0b446e82 in -[UINavigationControllerAccessibility(SafeCategory) _popViewControllerWithTransition:allowPoppingLast:] ()
#19 0x00ef0b10 in -[UINavigationController popViewControllerAnimated:] ()
#20 0x00ef297d in -[UINavigationController navigationBar:shouldPopItem:] ()
#21 0x00e7dabe in -[UINavigationBar _popNavigationItemWithTransition:] ()
#22 0x00e7da49 in -[UINavigationBar popNavigationItemAnimated:] ()
#23 0x0b42208c in -[UINavigationBarAccessibility(SafeCategory) popNavigationItemAnimated:] ()
#24 0x00e80507 in -[UINavigationBar _handleMouseUpAtPoint:] ()
#25 0x00e8074c in -[UINavigationBar touchesEnded:withEvent:] ()
#26 0x00e3fa30 in -[UIWindow _sendTouchesForEvent:] ()
#27 0x00e3fc56 in -[UIWindow sendEvent:] ()
#28 0x00e26384 in -[UIApplication sendEvent:] ()
#29 0x00e19aa9 in _UIApplicationHandleEvent ()
#30 0x02d37fa9 in PurpleEventCallback ()
#31 0x01e9e1c5 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ ()
#32 0x01e03022 in __CFRunLoopDoSource1 ()
#33 0x01e0190a in __CFRunLoopRun ()
#34 0x01e00db4 in CFRunLoopRunSpecific ()
#35 0x01e00ccb in CFRunLoopRunInMode ()
#36 0x02d36879 in GSEventRunModal ()
#37 0x02d3693e in GSEventRun ()
#38 0x00e17a9b in UIApplicationMain ()
#39 0x00002b72 in main (argc=1, argv=0xbffff620)
那里似乎没有任何有趣的东西（有吗？ ：P）似乎是苹果公司的所有内部人员。关于如何解决这个问题的任何想法？
There doesn't appear to be anything really interesting there (is there ever? :P) and appears to be all internals to Apple's stuff. Any ideas on how to get this problem to go away?
更新：即使我删除了我的视图控制器和属性之间的连接搜索显示控制器，但为它创建我自己的 IBOutlet ，它仍然崩溃。可能是错误的错误？
UPDATE: Even when I remove the connection between my view controller and the property for the Search Display Controller but create my own IBOutlet for it, it still crashes. Bad bug perhaps?
更新2：当我以编程方式创建自己的 UISearchDisplayController实例时（不通过故事板）并在 viewDidLoad 中创建它，一切都按预期的方式工作。
UPDATE 2: When I programmatically create my own instance of a UISearchDisplayController (not through the storyboard) and create it in viewDidLoad, everything works the way it is supposed to.
更新3：我能够在带有故事板的新项目中始终如一地重现此问题。我使用香草笔尖做了同样的事情，一切都按照它想象的方式工作。但是，如果我使用故事板和segue设置相同的东西，它会像在我的真实项目中一样爆炸。 :(
UPDATE 3: I am able to consistently reproduce this problem in a new project with a storyboard. I did the same thing using a vanilla nib and everything worked the way it was suppose to. However, if I setup the same thing using a storyboard and segue, it blows up just like it does in my real project. :(
RECAP ：以下是重新创建此问题的步骤：
RECAP: Here are the steps in recreating this issue:
- 在故事板中创建一个视图控制器，其中包含
UISearchDisplayController - 在导航堆栈上推送新的视图控制器
- 导致内存不足警告
- 将控制器弹出堆栈
- KABOOM！
- Create a view controller in a storyboard with a
UISearchDisplayController - Push a new view controller on the navigation stack
- Cause a low memory warning
- Pop the controller off of the stack
- KABOOM!
viewDidLoad 不甚至在此时调用第一个视图控制器，Apple的代码在此之前爆炸。
viewDidLoad does not even get called on the first view controller at this point, Apple's code blows up before then.
推荐答案
这就是我所做的（授予，这是一个解决方法，而不是修复Apple的错误）：
Here is what I did (granted, it's a workaround and not a fix for Apple's bug):
首先，在基础 UIViewController 我创建了名为 searchController 的属性：
First, in a base UIViewController I created a property called searchController:
@property (nonatomic, retain) IBOutlet UISearchDisplayController* searchController;
我添加了 UISearchB ar 在通过界面构建器中，以便在我的UI中有一个占位符。然后，在我的 viewDidLoad 中，我手动设置控制器并连接它：
I added a UISearchBar in through interface builder so that I have a placeholder in my UI for it. Then, in my viewDidLoad I manually setup the controller and wire it up:
UISearchDisplayController* searchController = [[UISearchDisplayController alloc]
initWithSearchBar:self.searchBar contentsController:self];
searchController.searchResultsDataSource = self;
searchController.searchResultsDelegate = self;
searchController.delegate = self;
self.searchController = searchController;
[searchController release];
在我的 viewDidUnload 我一定要清楚它出来了：
In my viewDidUnload I make sure to clear it out:
self.searchController = nil;
这篇关于UISearchDisplayController在viewDidUnload之后导致崩溃的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
