无效更新：部分中的行数无效

Question

我正在使用Microsoft Azure services开展项目。在删除行时，我收到此错误：

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (2) must be equal to the number of rows 
contained in that section before the update (2), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

表加载和删除行的代码如下：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
        return 3;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    //medicine list
    if (section == 0) {
        NSArray *sectionInfo = [self.fetchedResultsController1 fetchedObjects];
        return [sectionInfo count];

    }
    //allergy list
    else if (section == 1) {
        NSArray *sectionInfo = [self.fetchedResultsController2 fetchedObjects];
        return [sectionInfo count];

    }
    //notes list
    else if (section == 2){
        NSArray *sectionInfo = [self.fetchedResultsController3 fetchedObjects];
        return [sectionInfo count];
    }
    else
        return 0;
 }

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *cellIdentifier = @"mcell";
    MedicationTableViewCell *cell = (MedicationTableViewCell *)    [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];

    //  Add utility buttons 
    NSMutableArray *rightUtilityButtons = [NSMutableArray new];
    [rightUtilityButtons sw_addUtilityButtonWithColor: [UIColor colorWithRed:1.0f green:0.231f blue:0.188 alpha:1.0f] title:@"Delete"];

    switch (indexPath.section) {
        case 0: {
            NSManagedObject *item = [self.fetchedResultsController1 objectAtIndexPath:indexPath];
            cell.textLabel.text = [item valueForKey:@"name"];
            break;
        }
        case 1: {
            NSManagedObject *item = [self.fetchedResultsController2 objectAtIndexPath:[NSIndexPath indexPathForRow:indexPath.row inSection:0]];
            cell.textLabel.text = [item valueForKey:@"name"];
            break;
        }
        case 2: {
            NSManagedObject *item = [self.fetchedResultsController3 objectAtIndexPath: [NSIndexPath indexPathForRow:indexPath.row inSection:0]];
            cell.textLabel.text = [item valueForKey:@"title"];
            break;
        }
        default:
            break;
    }
    cell.rightUtilityButtons = rightUtilityButtons;
    cell.delegate = self;

    return cell;
}

- (void)swipeableTableViewCell:(SWTableViewCell *)cell didTriggerRightUtilityButtonWithIndex:(NSInteger)index {

 // Delete button is pressed
 NSIndexPath *cellIndexPath = [self.medicationsTableView indexPathForCell:cell];

 //fetchingg data from local store first
 NSManagedObject *item = [self.fetchedResultsController1 objectAtIndexPath:[NSIndexPath indexPathForRow:cellIndexPath.row inSection:0]];

   NSMutableArray *keys = [[NSMutableArray alloc] initWithObjects:@"id", @"name", @"userId", nil];
   NSMutableArray *values = [[NSMutableArray alloc] initWithObjects: [item valueForKey:@"id"], [item valueForKey:@"name"], [item valueForKey:@"userId"], nil];

    //creating dictionary of data
    NSDictionary *dict = [[NSDictionary alloc] initWithObjects:values forKeys:keys];

    //calling delete fucntion
    [self.authService deleteItem:self.syncTable withDict:dict completion:^{
    //removing row from table view
    [self.medicationsTableView reloadData];
    [self.medicationsTableView deleteRowsAtIndexPaths:@[cellIndexPath] withRowAnimation:UITableViewRowAnimationRight];
      }];
      break;
}

请告诉我哪里出错了。先谢谢!!!!

Answer 1

在- (void)swipeableTableViewCell: didTriggerRightUtilityButtonWithIndex:

您需要删除

[self.medicationsTableView reloadData]; 

或

[self.medicationsTableView deleteRowsAtIndexPaths:@[cellIndexPath] withRowAnimation:UITableViewRowAnimationRight];

因为在第一行调用reloadData时，它会使用新数据源重新加载tableview，并再次调用deleteRowsAtIndexPaths尝试删除之前已通过调用reloadData删除的行。

Answer 2

重要的是你需要使用

[self.medicationsTableView reloadData];

或

[self.medicationsTableView deleteRowsAtIndexPaths:@[cellIndexPath] withRowAnimation:UITableViewRowAnimationRight];

原因是，当调用tableview's reload data时，将从数据源中删除的行被删除，之后当为同一index path调用删除行api时（行已经是行）删除导致问题）

也就在删除表中的行之前，从数据源（self.fetchedResultsController1）中删除对象并调用

[self.medicationsTableView deleteRowsAtIndexPaths:@[cellIndexPath] withRowAnimation:UITableViewRowAnimationRight];

并且在完成上述行的删除动画之后，您可以调用（但不是必需的）

[self.medicationsTableView reloadData];