从表中删除单元格时出错

时间:2011-05-30 06:21:24

标签: iphone objective-c uitableview

当我从表中删除一个单元格时,我收到以下错误:

  

断言失败 - [UITableView _endCellAnimationsWithContext:],/ SourceCache / UIKit_Sim / UIKit-1448.89 / UITableView.m:995       严重的应用错误。代表发现了一个例外   NSFetchedResultsController期间的一个   调用-controllerDidChangeContent:。   无效更新:行数无效   在第0节中。行数   包含在现有部分之后   更新(5)必须等于   包含在其中的行数   更新前的部分(5),加或   减去插入的行数或   从该部分删除(0插入,   1删除)。 with userInfo(null)

以下是相关代码:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
    return [sectionInfo numberOfObjects];
}
-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) 
    {
        // Delete the managed object for the given index path
        NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
        [context deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];
        NSLog(@"fetched results : \n%@\n",[self.fetchedResultsController fetchedObjects]);

        // Commit the change.
        NSError *error = nil;

        // Update the array and table view.
        if (![managedObjectContext save:&error]) 
        {
            // Handle the error.
        }
        //[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];
    }
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}

#pragma mark - Fetched results controller delegate


- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
    [self.resultsTableView beginUpdates];
}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
    switch(type)
    {
        case NSFetchedResultsChangeInsert:
            [self.resultsTableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;

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

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath
{
    UITableView *tableView = self.resultsTableView;

    switch(type)
    {

        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

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

        case NSFetchedResultsChangeUpdate:
            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;

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

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

我尝试从上一个方法中移除[self.setsTableView reloadData];,但这也不起作用。

2 个答案:

答案 0 :(得分:1)

似乎是从表中删除单元格,但不是从表数据源中删除对象,这会产生不一致。 尝试添加类似的东西:

[[[self.fetchedResultsController sections] objectAtIndex:indexPath.section] removeObjectAtIndex:indexPath.row];

使用tableView:deleteRowsAtIndexes

numberOfRowsInSection:返回的数字必须与tableView中的行数相同,减去/加上您删除/添加的数字

答案 1 :(得分:0)

在上述所有方法中,将 self.fetchedResultsController 更改为fetchedResultsController。只在方法中保留self.fetchedResultsController


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
   return [[self.fetchedResultsController sections] count];
}
// - 尝试将managedObjectContext保留为成员变量,并使用以下setter //方法。

- (NSManagedObjectContext *)managedObjectContext {

if (managedObjectContext != nil) 
{
    return managedObjectContext;
}

NSPersistentStoreCoordinator *coordinator = [(AppDelegate *)[[UIApplication sharedApplication] delegate] persistentStoreCoordinator];   
if (coordinator != nil) {
    managedObjectContext = [[NSManagedObjectContext alloc] init];
    [managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return managedObjectContext;

}