coredata错误使tableView无法显示（NSFetchResultsController）

Question

CoreData: error: Serious application error.  An exception was caught from the delegate of 

NSFetchedResultsController during a call to -controllerDidChangeContent:.  Invalid update: invalid number of sections.  
The number of sections contained in the table view after the update (1) must be equal to the number of sections contained in the table view before the update (0), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted). with userInfo (null)

像这样的错误？我怎么知道？我的代码出了什么问题..我不明白这个错误..任何人都可以告诉我那是什么？我该如何解决这个问题呢？

节数始终为 1.. 为什么更新前从 0 开始？如何让表在更新之前识别出有 1 个且只有 1 个部分？

    -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
    {
        return [[self.FetchController sections] count];
    }

    -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
    {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.FetchController sections] objectAtIndex:section];
        /*int numberOfRow=[sectionInfo numberOfObjects]-(self.numberOf20SkipFromtheBeginning*20);
        numberOfRow = MIN(20,numberOfRow);*/
        //int numberOfRow=MIN(100,[sectionInfo numberOfObjects]);
        CalledRowCountingNotYetCallRowForSection=true;
        [self.tableViewA setBounces:YES];

        if([sectionInfo numberOfObjects]>100){
            //[Timer searchCriteriaChanged];
            CLog(@"Something Wrong This NumberOfRow: %d", [sectionInfo numberOfObjects]);
        }


        return [sectionInfo numberOfObjects];
    }

    -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
    {
        DLog(@"Function TableView AT listnewController");

        CalledRowCountingNotYetCallRowForSection =false;
        if ([self tableView:tableView numberOfRowsInSection:indexPath.section]==0)
        {
            DLog(@"Something is VERY WRONG. Number of Section: %d" ,indexPath.section);
        }
        DLog(@"Indexpath at cellForRowAtIndexPath : %d", indexPath);
        Business * theBiz=[self.FetchController objectAtIndexPath:indexPath];
        return theBiz.CustomCell;

    }

    -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
    {
        DLog(@"Function didselectrowatindexpath listnewcontroller");
        //[BNUtilitiesQuick UtilitiesQuick].currentBusiness=[[self.FetchController fetchedObjects] objectAtIndex:[indexPath row]+self.numberOf20SkipFromtheBeginning*20];
        [BNUtilitiesQuick UtilitiesQuick].currentBusiness=[[self.FetchController fetchedObjects] objectAtIndex:[indexPath row]];
        [BNUtilitiesQuick SafelyPushControllerAtNavigationController:[BNUtilitiesQuick NearbyIsiKota].mDetailBusiness atNavigationController:[BNUtilitiesQuick NearbyIsiKota].navigationController];
    }

    - (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
    DLog(@"controllerWillChangeContent: %@", controller);
    [self.tableViewA beginUpdates];

}


- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type {

    DLog(@"didChangeSection: %@", controller);

    switch(type) {
        case NSFetchedResultsChangeInsert:
            [self.tableViewA insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [self.tableViewA deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}


- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath {

    DLog(@"controller:%@\ndidChangeObject:%@\natIndexPath:%@\nforChangeType:%d\nnewIndexPath:%@\n",controller, anObject, indexPath, type, newIndexPath);

    UITableView *tableView = self.tableViewA;
    DLog(@"%@", self.tableViewA);
    switch(type) {
        case NSFetchedResultsChangeInsert:
                [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationRight];
            break;

        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationRight];
            break;

        case NSFetchedResultsChangeUpdate:

            //[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationLeft];
            //[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]withRowAnimation:UITableViewRowAnimationRight];
            //[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationNone];
            break;

        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationRight];
            [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]withRowAnimation:UITableViewRowAnimationRight];
            break;
    }

}


- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
    [self.tableViewA endUpdates];
}

Answer 1

这很可能是由于在 NSFetchedResultsController 不需要时为 NSFetchedResultsController 提供了一个 sectionNameKeyPath 造成的。

如果您提供 sectionNameKeyPath 但该键路径还没有值，则获取的结果控制器将报告该表有零个部分。如果该键路径获取一个值，则获取的结果控制器将报告该表现在有一个或多个部分。

要修复此问题，请确保在初始化获取的结果控制器时 sectionNameKeyPath 为空。您还可以硬连线 numberOfSectionsInTableView: 以始终返回零或一。