xcode 出现断言失败错误

Getting An Assertion Failure Error

提问by shakthi

I am getting the following error when loading one of my views that has a UITableView in it. Does anyone know how to fix it? I have already tried deleting the (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPathmethod, but that didn't help.

加载其中包含 UITableView 的视图之一时，出现以下错误。有谁知道如何修理它？我已经尝试删除该(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath方法，但这没有帮助。

I'm thinking it has to do with the table's delegate not being updated properly with numberOfRowsInSection or something.

我认为这与表的委托没有用 numberOfRowsInSection 或其他东西正确更新有关。

*** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit/UIKit-1448.89/UITableView.m:995
2011-06-05 00:38:12.116 App[14523:707] Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (5) must be equal to the number of rows contained in that section before the update (5), plus or minus the number of rows inserted or deleted from that section (0 inserted, 3 deleted). with userInfo (null)

Here is my code:

这是我的代码：

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (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];
    }
}

#pragma mark - Fetched results controller

- (NSFetchedResultsController *)fetchedResultsController
{
    if (fetchedResultsController != nil)
    {
        return fetchedResultsController;
    }
    // Create the fetch request for the entity.
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Set" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];
    [fetchRequest setPredicate:[NSPredicate predicateWithFormat: @"sets == %@", self.exercise]];
    // Set the batch size to a suitable number.
    [fetchRequest setFetchBatchSize:20];
    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:YES];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

    [fetchRequest setSortDescriptors:sortDescriptors];

    // Edit the section name key path and cache name if appropriate.
    // nil for section name key path means "no sections".
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;

    [aFetchedResultsController release];
    [fetchRequest release];
    [sortDescriptor release];
    [sortDescriptors release];

    NSError *error = nil;
    if (![self.fetchedResultsController performFetch:&error])
    {
        /*
         Replace this implementation with code to handle the error appropriately.

         abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
         */
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
    NSLog(@"fetched results : \n%@\n",[self.fetchedResultsController fetchedObjects]);
    NSLog(@"fetch count: %i", [fetchedResultsController.fetchedObjects count]);
    return self.fetchedResultsController;
}    
#pragma mark - Fetched results controller delegate


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

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

        case NSFetchedResultsChangeDelete:
            [self.setsTableView 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.setsTableView;

    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.setsTableView endUpdates];

    [self.setsTableView reloadData];
}

回答by shakthi

is Try uncommenting [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];

是尝试取消注释 [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];

Please note:

请注意：

(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

should return a value 1 less than that of before calling 'deleteRows..'

应该返回一个比调用 'deleteRows..' 之前的值小1的值

Basic problem is this: You are instructing UI to delete one of the rows, but not removing that row from the back end.

基本问题是：您正在指示 UI 删除其中一行，但不会从后端删除该行。

回答by arturgrigor

If you are using the code from CoreDataBooks sample you might want to change this:

如果您使用的是 CoreDataBooks 示例中的代码，您可能需要更改此内容：

- (void)addControllerContextDidSave:(NSNotification*)saveNotification {

    NSManagedObjectContext *context = [fetchedResultsController managedObjectContext];
    // Merging changes causes the fetched results controller to update its results
    [context mergeChangesFromContextDidSaveNotification:saveNotification];  
}

with

和

- (void)addControllerContextDidSave:(NSNotification*)saveNotification {
        double delayInSeconds = 1.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            NSManagedObjectContext *context = [fetchedResultsController managedObjectContext];
            // Merging changes causes the fetched results controller to update its results
            [context mergeChangesFromContextDidSaveNotification:saveNotification];
        }); 
    }

This will prevent NSFetchedResultsController from refreshing while the tableView is not visible because of the UINavigationController transition.

这将阻止 NSFetchedResultsController 在 tableView 由于 UINavigationController 转换而不可见时刷新。

Of course this thing occurs only in simulator, because on the device the insert will take longer than the [self dismissModalViewControllerAnimated:YES] animation.

当然，这件事只发生在模拟器中，因为在设备上插入将花费比 [self deniedModalViewControllerAnimated:YES] 动画更长的时间。

回答by rakeshNS

In my case when I called [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];only, I got this type of error. I solved this by removing the object from Array (from this array I am displaying data.) and called [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];

在我[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];只打电话的情况下，我遇到了这种类型的错误。我通过从 Array 中删除对象来解决这个问题（从这个数组中我正在显示数据。）并调用[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];

回答by Bob

I put each section elements in separated arrays. Then put them into another array( arrayWithArray). My solution here for this problem:

我将每个部分元素放在单独的数组中。然后将它们放入另一个数组（arrayWithArray）中。我在这里针对这个问题的解决方案：

[quarantineMessages removeObject : message];
[_tableView beginUpdates];
if([[arrayWithArray objectAtIndex: indPath.section] count]  > 1)
{
    [_tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indPath] withRowAnimation:UITableViewRowAnimationBottom];
}
else
{
    [_tableView deleteSections:[NSIndexSet indexSetWithIndex:indPath.section]
              withRowAnimation:UITableViewRowAnimationFade];
}
[_tableView endUpdates];