我面临核心数据一个非常奇怪的问题。让我们描述一下:
定义
假设我有两个模型，ModelA和ModelB。在数据模型中，ModelA将ModelB称为一对多关联，因此ModelB与ModelA一对一关联。
更新
当应用程序启动时(尤其是在首次启动时)，或者在用户询问时，我必须为每个ModelB实例创建或更新所有ModelA实例。 ModelA实例是预定的。对于每个ModelA实例，我大约有200个ModelB实例。
我使用这样的代码:
ModelB *model = [NSEntityDescription insertNewObjectForEntityForName:@"ModelB"
inManagedObjectContext:context];
model.value = [NSNumber numberWithDouble:myValue];
model.modelA = modelA; // I pass modelA as a parameter to the function
[modelA addModelBObject:model];
错误
有时，并且只有有时，我在此行收到
EXC_BAD_ACCESS错误:model.value = [NSNumber numberWithDouble:myValue];
EXC_BAD_ACCESS，仅此而已。真正奇怪的错误
我试图以不同的方式设置该值，但没有任何改变。然后，我尝试对
retain进行NSNumber，但是什么都没有改变。然后，最后，我尝试对创建的模型进行retain编码，然后得到了通常的EXC_BAD_ACCESS，但是对应于模型的创建，即在这里:ModelB *model = [[NSEntityDescription insertNewObjectForEntityForName:@"ModelB"
inManagedObjectContext:context] retain];
您对如何解决此问题有任何想法吗？难道我做错了什么？
顺便说一句，如果我减慢很多速度(例如，每次创建新模型时都保存上下文)，就不会出现这个问题，但这确实减慢了整个应用程序的运行速度...
编辑
在极少数情况下，我会得到以下堆栈跟踪:
Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null)
2011-06-15 11:36:59.864 myApp[457:607] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFSet addObject:]: attempt to insert nil'
*** Call stack at first throw:
(
0 CoreFoundation 0x313dc64f __exceptionPreprocess + 114
1 libobjc.A.dylib 0x34b3dc5d objc_exception_throw + 24
2 CoreFoundation 0x313dc491 +[NSException raise:format:arguments:] + 68
3 CoreFoundation 0x313dc4cb +[NSException raise:format:] + 34
4 CoreFoundation 0x31351089 -[__NSCFSet addObject:] + 152
5 CoreData 0x35136dd9 -[NSManagedObjectContext(_NSInternalChangeProcessing) _processPendingUpdates:] + 524
6 CoreData 0x350f4b3d -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] + 724
7 CoreData 0x351363a5 -[NSManagedObjectContext processPendingChanges] + 16
8 CoreData 0x350d027f _performRunLoopAction + 126
9 CoreFoundation 0x313b3a35 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 16
10 CoreFoundation 0x313b5465 __CFRunLoopDoObservers + 412
11 CoreFoundation 0x313b675b __CFRunLoopRun + 854
12 CoreFoundation 0x31346ec3 CFRunLoopRunSpecific + 230
13 CoreFoundation 0x31346dcb CFRunLoopRunInMode + 58
14 GraphicsServices 0x3658841f GSEventRunModal + 114
15 GraphicsServices 0x365884cb GSEventRun + 62
16 UIKit 0x368ded69 -[UIApplication _run] + 404
17 UIKit 0x368dc807 UIApplicationMain + 670
18 myApp 0x000028cf main + 82
19 myApp 0x00002878 start + 40
)
terminate called after throwing an instance of 'NSException'
这是异常的堆栈跟踪:
#0 0x313f1460 in __CFBasicHashAddValue ()
#1 0x3133fff8 in CFBasicHashAddValue ()
#2 0x31344162 in CFSetAddValue ()
#3 0x31351012 in -[__NSCFSet addObject:] ()
#4 0x3514211a in _PFFastMOCObjectWillChange ()
#5 0x3512ed46 in _PF_ManagedObject_WillChangeValueForKeyIndex ()
#6 0x35132e7e in _sharedIMPL_setvfk_core ()
#7 0x3513316a in _svfk_2 ()
#8 0x0003b750 in -[_TassoStorico setValoreValue:] (self=0x6d97bf0, _cmd=0x49064, value_=1.02600002) at _TassoStorico.m:87
#9 0x0001b62e in -[EuriborParser(hidden) readStoricoForzato] (self=0x74200d0, _cmd=0x48ff7) at EuriborParser.m:236
#10 0x31349f02 in -[NSObject(NSObject) performSelector:withObject:] ()
#11 0x000441c4 in -[MBProgressHUD launchExecution] (self=0x90a6ff0, _cmd=0x4b83f) at MBProgressHUD.m:482
#12 0x352b3388 in -[NSThread main] ()
#13 0x353255cc in __NSThread__main__ ()
#14 0x34e20310 in _pthread_start ()
#15 0x34e21bbc in thread_start ()
最佳答案
CoreData不是线程安全的；看起来这是您的问题，请尝试查看此SO question
关于objective-c - 核心数据 : solve a strange EXC_BAD_ACCESS error，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/6355126/