问题
I have a tableView hooked up to a FRC (Fetched Results Controller) , I also have two contexts , namely backgroundContext initialised in a private queue and a mainContext initialised on the main queue. I also have setup the didSaveNotification to pass the objects from one context to another. When ever i save some data in the backgroundContext it saves successfully and FRC updates ,but if i repeat the process again the app crashes with an error
'The left hand side for an ALL or ANY operator must be either an NSArray or an NSSet.'
The saving is done through a form which is presented modally. The same viewController works fine if presented in other viewControllers . but crashes only in one particular one. But again other that presenting the Form no other extra stuff is being done.
Here's my entire crash report.
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'The left hand side for an ALL or ANY operator must be either an NSArray or an NSSet.' * First throw call stack: ( 0 CoreFoundation 0x0000000103575495 exceptionPreprocess + 165 1 libobjc.A.dylib
0x0000000102fbb99e objc_exception_throw + 43 2 Foundation
0x00000001003c706b -[NSPredicateOperator performOperationUsingObject:andObject:] + 826 3 Foundation
0x00000001003c6c1e -[NSComparisonPredicate evaluateWithObject:substitutionVariables:] + 314 4 Foundation
0x00000001003c6ae2 -[NSPredicate evaluateWithObject:] + 19 5
CoreData 0x0000000102d61d06 -[NSFetchedResultsController(PrivateMethods) _objectInResults:] + 102 6 CoreData 0x0000000102d630f7 -[NSFetchedResultsController(PrivateMethods) _preprocessUpdatedObjects:insertsInfo:deletesInfo:updatesInfo:sectionsWithDeletes:newSectionNames:treatAsRefreshes:] + 519 7 CoreData 0x0000000102d642d5 -[NSFetchedResultsController(PrivateMethods) _managedObjectContextDidChange:] + 1781 8 CoreFoundation 0x00000001035cad9c __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER + 12 9 CoreFoundation 0x000000010352d51d _CFXNotificationPost + 2381 10 Foundation 0x000000010035b7fa -[NSNotificationCenter postNotificationName:object:userInfo:] + 68 11 CoreData
0x0000000102c9048a -[NSManagedObjectContext(_NSInternalNotificationHandling) _postObjectsDidChangeNotificationWithUserInfo:] + 74 12 CoreData 0x0000000102d16c8b -[NSManagedObjectContext(_NSInternalChangeProcessing) _createAndPostChangeNotification:withDeletions:withUpdates:withRefreshes:] + 331 13 CoreData 0x0000000102c8c9cc -[NSManagedObjectContext(_NSInternalChangeProcessing) _postRefreshedObjectsNotificationAndClearList] + 108 14 CoreData 0x0000000102c8c5e4 -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] + 2804 15 CoreData 0x0000000102c663cb _performRunLoopAction + 267 16 CoreFoundation
0x0000000103540dc7 CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 23 17 CoreFoundation 0x0000000103540d37 __CFRunLoopDoObservers + 391 18 CoreFoundation 0x0000000103520522 __CFRunLoopRun + 946 19 CoreFoundation
0x000000010351fd83 CFRunLoopRunSpecific + 467 20 GraphicsServices
0x00000001037ecf04 GSEventRunModal + 161 21 UIKit
0x00000001011bde33 UIApplicationMain + 1010 22 Expense_Manager
0x0000000100001d13 main + 115 23 libdyld.dylib
0x000000010420c7e1 start + 0 ) libc++abi.dylib: terminating with uncaught exception of type NSException
Thanks in advance.
回答1:
Okay i actually found out why this was happening a few days ago. There was a notification being fired off when the form dismissed which reloaded a tableView from another viewController hooked up to an FRC sharing the same context. Once I removed itself as an observer in viewDidDisappear it did not crash. :) I hope this helps incase someone is facing the same problem.
来源：https://stackoverflow.com/questions/23877842/crash-when-fetched-results-controller-updates-table-after-saving-a-background-mo