ios - 奇怪的问题 - "The fetched object at index x has an out of order section name"

Question

我收到以下错误消息:

CoreData: error: (NSFetchedResultsController) The fetched object at index 5 has an out of order section name 'James. Objects must be sorted by section name'
Unresolved search error Error Domain=NSCocoaErrorDomain Code=134060 "The operation couldn’t be completed. (Cocoa error 134060.)" UserInfo=0xaa07530 {reason=The fetched object at index 5 has an out of order section name 'James. Objects must be sorted by section name'}, {
    reason = "The fetched object at index 5 has an out of order section name 'James. Objects must be sorted by section name'";
}

我已经在 SO 上浏览了无数答案，大多数最终指向使用不区分大小写的比较作为答案，但是正如您在下面看到的，我的获取请求已经设置为执行此操作:

<NSFetchRequest: 0xc082bd0> (entity: InviteeModel; predicate: (eventId == 148 AND typeOf != "InviteeTypeOfServerContact"); sortDescriptors: ((
    "(lastName, ascending, caseInsensitiveCompare:)",
    "(firstName, ascending, caseInsensitiveCompare:)"
)); batch size: 1000; type: NSManagedObjectResultType; )

我似乎已经将范围缩小到我有两个姓氏相同的受邀者(即 HENRY JAMES 和 Henry James)的情况，然后我得到上面的错误，说 James 不正常。如果我将两个姓氏都更改为 James 或 JAMES 那么它有效吗？!？!？

这是创建获取请求的代码:

NSFetchRequest *fetchRequest = [self buildFetchRequest];

// We have to reset the fetched results controller if the sort changes.
// Because otherwise the scrolling index will be inaccurate.
if (self.fetchedResultsController) {
    if (![self.fetchedResultsController.sectionNameKeyPath isEqualToString:self.sortBy]) {
        self.fetchedResultsController = nil;
    }
}


if (!self.fetchedResultsController) {

    NSManagedObjectContext *context = self.event.managedObjectContext;

    NSString *sectionNameKeyPath = nil;
    if (self.sortBy == DefaultSortBy) {

        sectionNameKeyPath = @"sectionChar";
    }
    else {

        sectionNameKeyPath = self.sortBy;
        if ([self.sortBy isEqualToString:@"rsvpState"] || [self.sortBy isEqualToString:@"checkedIn"]) {
            sectionNameKeyPath = @"lastName";
        }
    }

    NSFetchedResultsController *fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest 
                                                                                               managedObjectContext:context 
                                                                                                 sectionNameKeyPath:sectionNameKeyPath
                                                                                                          cacheName:nil];
    fetchedResultsController.delegate = self;
    self.fetchedResultsController = fetchedResultsController;

这是来自 buildFetchRequest 的一段，它添加了 sortDescriptors:

        NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:self.sortBy
                                                                       ascending:self.shouldSortAscending
                                                                        selector:@selector(caseInsensitiveCompare:)];

        // Add the default sorts (last, first).
        NSSortDescriptor *lastSort = nil;
        NSSortDescriptor *firstSort = nil;
        if (![self.sortBy isEqualToString:@"lastName"]) {
            lastSort = [NSSortDescriptor sortDescriptorWithKey:@"lastName"
                                                     ascending:YES
                                                      selector:@selector(caseInsensitiveCompare:)];
        }
        if (![self.sortBy isEqualToString:@"firstName"]) {
            firstSort = [NSSortDescriptor sortDescriptorWithKey:@"firstName"
                                                      ascending:YES
                                                       selector:@selector(caseInsensitiveCompare:)];
        }

        NSArray *sorts = nil;

        if (lastSort && firstSort) {
            sorts = [[NSArray alloc] initWithObjects:sortDescriptor, lastSort, firstSort, nil];
        }
        else if (lastSort) {
            sorts = [[NSArray alloc] initWithObjects:sortDescriptor, lastSort, nil];
        }
        else {
            sorts = [[NSArray alloc] initWithObjects:sortDescriptor, firstSort, nil];
        }

        [fetchRequest setSortDescriptors:sorts];

任何想法，这让我发疯。

Answer 1

您正在设置与第一个排序描述符键不同的获取结果 Controller 部分名称键路径。

   NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] 
           initWithKey:self.sortBy 
           ascending:self.shouldSortAscending
           selector:@selector(caseInsensitiveCompare:)];

关键是self.sortBy。

if ([self.sortBy isEqualToString:@"rsvpState"] || 
    [self.sortBy isEqualToString:@"checkedIn"]) {
       sectionNameKeyPath = @"lastName";
}

键不是self.sortBy。

这应该会导致您看到的错误。