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在将节标题添加到我的应用程序中的一个表之前，我能够使用 commitEditingStyle 函数删除行而没有任何问题。我决定实现部分标题，以便用户更轻松地查看按日期添加到表中的项目。此功能工作正常。在实现节标题后，我在删除行时遇到了问题，但感谢 stackoverflow 上好心人的帮助，问题得到了部分解决。经过一些测试后，我意识到如果这些行在同一部分中，并且我尝试从该部分的第一行开始依次删除多行，则第一行删除正常，但尝试删除第二行会导致应用程序崩溃。如果我按顺序删除第一行以外的所有行，然后最后删除第一行，它工作正常。Xcode 没有

下面是 cellForRowAtIndexPath 函数的代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    AgendaCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[AgendaCell alloc]
                initWithStyle:UITableViewCellStyleDefault
                reuseIdentifier:CellIdentifier];
    }
    NSString *strDate = [dateArray objectAtIndex:indexPath.section];
    NSMutableArray *dateSection = [tempDict objectForKey:strDate];

    NSManagedObject *object = [dateSection objectAtIndex:indexPath.row];
    cell.sessionNameLabel.text = [object valueForKey:@"sessionname"];
    cell.sessionNameLabel.textColor = [UIColor blueColor];
    cell.sessionDateLabel.text = [object valueForKey:@"sessiondate"];
    cell.sessionDateLabel.textColor = [UIColor brownColor];
    cell.sessionTimeLabel.text = [object valueForKey:@"sessiontime"];
    cell.sessionTimeLabel.textColor = [UIColor brownColor];

    return cell;

}

这是我的表格刷新功能的代码：

- (void) refreshTable
    {

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Sessnotes"   inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    [fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"agenda == 'Yes'"]];

    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]  initWithKey:@"sessiondate" ascending:YES];
    NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];

    [fetchRequest setSortDescriptors:sortDescriptors];

     NSArray *results = [self.managedObjectContext executeFetchRequest:fetchRequest   error:nil];

        [self.refreshControl endRefreshing];
        self.objects = results;

    if (results.count == 0) {
        NSString *message = @"You have not added any sessions to your planner.";
        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"Notification"
                                                       message:message
                                                      delegate:self
                                             cancelButtonTitle:@"Ok"
                                             otherButtonTitles:nil,nil];
        [alertView show];
    }
    else if (results.count > 0){
    tempDict = nil;
    tempDict = [[NSMutableDictionary alloc] init];

    NSString *strPrevDate= [[results objectAtIndex:0] valueForKey:@"sessiondate"];
    NSLog(@"strPrevDate value is: %@", strPrevDate);
    NSString *strCurrDate = nil;
    NSMutableArray *tempArray = [[NSMutableArray alloc] init];
    //Add the Similar Date data in An Array then add this array to Dictionary
    //With date name as a Key. It helps to easily create section in table.
    for(int i=0; i< [results count]; i++)
    {
        strCurrDate = [[results objectAtIndex:i] valueForKey:@"sessiondate"];

        if ([strCurrDate isEqualToString:strPrevDate])
        {
            [tempArray addObject:[results objectAtIndex:i]];
        }
        else
        {
            [tempDict setValue:[tempArray copy] forKey:strPrevDate];

            strPrevDate = strCurrDate;
            [tempArray removeAllObjects];
            [tempArray addObject:[results objectAtIndex:i]];
        }
    }
    //Set the last date array in dictionary
    [tempDict setValue:[tempArray copy] forKey:strPrevDate];

    NSArray *tArray = [tempDict allKeys];
    //Sort the array in ascending order
    dateArray = [tArray    sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
    }

        [self.tableView reloadData];

}

以下是 commitEditingStyle 函数的代码：

- (void)tableView:(UITableView *)tableView commitEditingStyle:   (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        //add code here for when you hit delete

        NSManagedObject *object = [self.objects objectAtIndex:indexPath.row];

        NSManagedObjectContext *context = [self managedObjectContext];

        [context deleteObject:[context objectWithID:[object objectID]]];

        NSError *error = nil;
        // Save the object to persistent store
        if (![context save:&error]) {
            NSLog(@"Can't Save! %@ %@", error, [error localizedDescription]);
        }

        NSMutableArray *array = [self.objects mutableCopy];
        [array removeObjectAtIndex:indexPath.row];
        self.objects = array;
        [tableView reloadData];
    }
}
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1 回答 1

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前面有几件事。每次您想重新加载 tableview 时，我都不会发出 fetch 请求。你应该看看 NSFetchedResultsController。它会自动将数据绑定到您的 tableview 并根据来自相同 NSManagedObjectContexts 的更新或来自其他上下文的更新消息为您进行刷新，并为您批处理它们。

回答你原来的问题。我会尝试先从数组中删除对象，然后删除 NSManagedObject ，然后你可以使用一些 tableview 技巧：

NSManagedObject *managedObject = self.array[indexPath.row];
[self.array removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation: UITableViewRowAnimationAutomatic];
[context deleteObject:managedObject];

我可能是错的，但有可能你没有完成一个错误。希望有帮助。

于 2013-10-17T13:34:36.843 回答