NSFetchedResultsController的indexPathForObject函数

问题描述

在使用NSFetchedResultsController的iOS 14以后，我一直面临崩溃。

前提条件：

我正在使用NSFetchRequest初始化NSFetchedResultsController，并且在获取请求中，我正在使用propertiesToFetch来获取单个属性，resultType为NSDictionaryResultType，而returndistinctResults为YES，以获取不同的结果。以下是用于NSFetchedResultsController对象的获取请求。

- (NSFetchRequest *)fetchRequest {
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:NsstringFromClass([ABC class])];
    request.predicate = [nspredicate predicateWithFormat:@"id = %@ AND removed = NO",[LMSAppDelegate sharedDelegate].module.cycleID];
    request.returnsdistinctResults = YES;
    request.propertiesToFetch = @[@"xyz"];
    request.resultType = NSDictionaryResultType;
    request.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"xyz" ascending:YES]];

    return request;
}

NSFetchedResultsController用作我们应用程序中表的数据源。

问题：

这在低于iOS 14版本的系统中仍能正常工作，但在iOS 14及更高版本（14.1）中已开始崩溃，其原因是我们传递的用于获取函数'indexPathForObject'中的索引路径的字典是未能返回异常识别器无法识别的索引路径（附加日志）。下面的功能崩溃了。

- (NSIndexPath *)indexPathForObject:(id)object {
    return [self.fetchedResultsController indexPathForObject:object];
}

我没有找到可用于相同目的的任何文档或新API。

请让我知道如何解决此问题。

Stack Trace:

2020-10-27 11:50:22.165740+0530 XYZ[70020:1505717] -[__NSSingleEntryDictionaryI objectID]: unrecognized selector sent to instance 0x600007efeb80
2020-10-27 11:50:22.245891+0530 XYZ[70020:1505717] *** Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '-[__NSSingleEntryDictionaryI objectID]: unrecognized selector sent to instance 0x600007efeb80'
*** First throw call stack:
(
    0   CoreFoundation                      0x000000010b681126 __exceptionPreprocess + 242
    1   libobjc.A.dylib                     0x000000010b511f78 objc_exception_throw + 48
    2   CoreFoundation                      0x000000010b68fc6f +[NSObject(NSObject) instanceMethodSignatureForSelector:] + 0
    3   CoreFoundation                      0x000000010b685666 ___forwarding___ + 1489
    4   CoreFoundation                      0x000000010b687698 _CF_forwarding_prep_0 + 120
    5   CoreData                            0x00000001051e3f23 -[_NSDefaultSectionInfo indexOfObject:] + 80
    6   CoreData                            0x000000010533671d -[NSFetchedResultsController indexPathForObject:] + 151
    7   Lido_mPilot                         0x0000000101ed4ac3 -[LMSFetchedResultsDataSource indexPathForObject:] + 99
    8   Lido_mPilot                         0x000000010238b1dc -[LMSFleetTableViewDataSource indexPathForObject:] + 140
    9   Lido_mPilot                         0x0000000101e160ad -[LMSFleetTableViewController viewWillAppear:] + 365
    10  UIKitCore                           0x0000000122115fb2 -[UIViewController _setViewAppearState:isAnimating:] + 654
    11  UIKitCore                           0x00000001221167db -[UIViewController __viewWillAppear:] + 106
    12  UIKitCore                           0x0000000122047534 -[UINavigationController _startTransition:fromViewController:toViewController:] + 726
    13  UIKitCore                           0x0000000122048371 -[UINavigationController _startDeferredTransitionIfNeeded:] + 851
    14  UIKitCore                           0x00000001220496dc -[UINavigationController __viewWillLayoutSubviews] + 150
    15  UIKitCore                           0x0000000122029f1e -[UILayoutContainerView layoutSubviews] + 217
    16  UIKitCore                           0x0000000122d9c9ce -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 2874
    17  QuartzCore                          0x00000001099e9d87 -[CALayer layoutSublayers] + 258
    18  QuartzCore                          0x00000001099f0239 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 575
    19  QuartzCore                          0x00000001099fbf91 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 65
    20  QuartzCore                          0x000000010993c078 _ZN2CA7Context18commit_transactionEPNS_11TransactionEdPd + 496
    21  QuartzCore                          0x0000000109972e13 _ZN2CA11Transaction6commitEv + 783
    22  UIKitCore                           0x00000001228701a3 _afterCACommitHandler + 164
    23  CoreFoundation                      0x000000010b5ee6b3 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    24  CoreFoundation                      0x000000010b5e8f3f __CFRunLoopDoObservers + 547
    25  CoreFoundation                      0x000000010b5e94e2 __CFRunLoopRun + 1113
    26  CoreFoundation                      0x000000010b5e8b9e CFRunLoopRunSpecific + 567
    27  GraphicsServices                    0x000000010e2e3db3 GSEventRunModal + 139
    28  UIKitCore                           0x000000012283faf3 -[UIApplication _run] + 912
    29  UIKitCore                           0x0000000122844a04 UIApplicationMain + 101
    30  Lido_mPilot                         0x0000000102421ce1 main + 193
    31  libdyld.dylib                       0x000000010cf64415 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '-[__NSSingleEntryDictionaryI objectID]: unrecognized selector sent to instance 0x600007efeb80'
terminating with uncaught exception of type NSException
CoreSimulator 732.17 - Device: iPad Pro (9.7-inch) (FE6E057B-B3C6-495D-9305-182325E6C237) - Runtime: iOS 14.0 (18A372) - DeviceType: iPad Pro (9.7-inch)

谢谢

解决方法

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ios ios ios14 nsfetchedresultscontroller objective-c swift swift swift swift

NSFetchedResultsController的indexPathForObject函数

问题描述

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