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Home/ Questions/Q 3988554
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Editorial Team
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Editorial Team
Asked: May 20, 20262026-05-20T06:15:58+00:00 2026-05-20T06:15:58+00:00

I am building an app with use of core data. My RootViewController, loaded by

  • 0

I am building an app with use of core data. My RootViewController, loaded by the appDelegate is mostly stock from the template. However I have changed the entity name to “Clocks” and added a bunch of rows.

My RootViewController presents an MVC which has a UINavigationController. When I save data to my database the UINavigationController class saved the data using [[UIApplication sharedApplication]delegate] to access my appDelegate which actually preforms the save action.
Editing data goes the same way, but instead of calling the insert function in my app delegate, it calls the update function.

Now, all this goes fine.. perfectly actually. BUT… after a few times just opening edit and saving in the view my app crashes. It does this both in the simulator and on my iPhone 4. This is an example of what I mean (Movie): http://dl.dropbox.com/u/3077127/has_been_invalidated.mov

This is the code of my RootViewController.m:

#import "RootViewController.h"
#import "RootViewControllerClockCell.h"
#import "RootViewControllerClockCellFooter.h"
#import "configuration.h"
#import "AddClockViewController.h"
#import "clockAppDelegate.h"

#import "AddClockNavigationController.h"

@interface RootViewController ()
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath;
@end


@implementation RootViewController

@synthesize fetchedResultsController=fetchedResultsController_, managedObjectContext=managedObjectContext_;


#pragma mark -
#pragma mark View lifecycle

- (void)viewDidLoad {
    [super viewDidLoad];

    [self setTitle:NSLocalizedString(@"Alarms", @"AddClockNavigationController")];

    // Set up the edit and add buttons.
    self.navigationItem.leftBarButtonItem = self.editButtonItem;

    UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(showAddAlarmView)];
    self.navigationItem.rightBarButtonItem = addButton;
    [addButton release];

    [self.tableView setSeparatorStyle:UITableViewCellSeparatorStyleNone];
    [self.tableView setBackgroundColor:[UIColor clearColor]];
    [self.tableView setBackgroundView:[[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"clockTableBackground"]] autorelease]];
    [self.tableView setAllowsSelectionDuringEditing:YES];

    if (managedObjectContext_ == nil) 
    { 
        managedObjectContext_ = [(ClockAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; 
        NSLog(@"After managedObjectContext: %@",  managedObjectContext_);
    }

    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate=self;
    locationManager.desiredAccuracy=kCLLocationAccuracyBest;

    [locationManager startUpdatingLocation];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {

    location = newLocation.coordinate;
    [locationManager stopUpdatingLocation];

    [self.tableView reloadData];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [locationManager stopUpdatingLocation];

    [super viewWillDisappear:animated];
}


// Implement viewWillAppear: to do additional setup before the view is presented.
- (void)viewWillAppear:(BOOL)animated {
    [locationManager startUpdatingLocation];

    [super viewWillAppear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    if ([Configuration isIpad])
    {
        return YES;
    }
    else {
        return (interfaceOrientation == UIInterfaceOrientationPortrait);
    }
}

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath {

    // @TODO
    // Remove unused function
}

- (void)showAddAlarmView
{
    AddClockNavigationController *viewController = [[AddClockNavigationController alloc] initWithNibName:@"AddClockNavigationController" bundle:nil];

    [[self navigationController] presentModalViewController:viewController animated:YES];
    [viewController release];
}

#pragma mark -
#pragma mark Add a new object

- (void)setEditing:(BOOL)editing animated:(BOOL)animated
{
    [super setEditing:(BOOL)editing animated:(BOOL)animated];
    self.navigationItem.rightBarButtonItem.enabled = !editing;
}

#pragma mark -
#pragma mark Table view data source

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

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];

    int retValue = [sectionInfo numberOfObjects];

    retValue++;

    return retValue;
}

// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:indexPath.section];

    if (indexPath.row < [sectionInfo numberOfObjects])
    {
        static NSString *CellIdentifier = @"RootViewControllerClockCell";
        RootViewControllerClockCell *cell = (RootViewControllerClockCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

        if (cell == nil){
            NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"RootViewControllerClockCell" owner:nil options:nil];

            for(id currentObject in topLevelObjects)
            {
                if([currentObject isKindOfClass:[RootViewControllerClockCell class]])
                {
                    cell = (RootViewControllerClockCell *)currentObject;
                    break;
                }
            }
        }

        // Configure the cell.
        NSManagedObject *managedObject = [[self.fetchedResultsController objectAtIndexPath:indexPath] retain];

        [[cell titleText] setText:[[managedObject valueForKey:@"title"] description]];

        UISwitch *mySwitch = [[[UISwitch alloc] initWithFrame:CGRectZero] autorelease];
        [cell addSubview:mySwitch];
        cell.accessoryView = mySwitch;
        [cell setSelectionStyle:UITableViewCellSelectionStyleNone];

        [mySwitch setTag:indexPath.row];

        BOOL isOn = [(NSNumber*)[managedObject valueForKey:@"active"] boolValue];

        [(UISwitch *)cell.accessoryView setOn:isOn];
        [(UISwitch *)cell.accessoryView addTarget:self action:@selector(setClockEnabled:) forControlEvents:UIControlEventValueChanged];

        [cell setEditingAccessoryType:UITableViewCellAccessoryDisclosureIndicator];

        [currentLocation release];
        [cellLocation release];
        [managedObject release];

        return cell;
    }
    else {
        static NSString *CellIdentifier = @"RootViewControllerClockCellFooter";
        RootViewControllerClockCellFooter *cell = (RootViewControllerClockCellFooter*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

        if (cell == nil){
            NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"RootViewControllerClockCellFooter" owner:nil options:nil];

            for(id currentObject in topLevelObjects)
            {
                if([currentObject isKindOfClass:[RootViewControllerClockCellFooter class]])
                {
                    cell = (RootViewControllerClockCellFooter *)currentObject;
                    break;
                }
            }
        }

        return cell;
    }
}

- (NSString*)distanceToString:(double)distance
{
    NSString *returnString = @"";

    if (distance < 1000)
    {
        returnString = [NSString stringWithFormat:@"%gm", round(distance)];
    }
    else {
        returnString = [NSString stringWithFormat:@"%gkm", round(distance/1000)];
    }

    return returnString;
}

- (void)setClockEnabled:(UISwitch*)sender
{
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:sender.tag inSection:0];

    NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];
    [managedObject setValue:[NSNumber numberWithBool:sender.on] forKey:@"active"];

    NSError *error = nil;
    if (![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();
    }
}

// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:indexPath.section];

    if ((indexPath.row > [sectionInfo numberOfObjects]-1) || [self.tableView numberOfRowsInSection:indexPath.section] == 1)
        return NO;
    else
        return YES;
}

// Override to support editing the table view.
- (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]];

        // Save the context.
        NSError *error = nil;
        if (![context save:&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();
        }

        if ([self.tableView numberOfRowsInSection:0] == 1)
        {
            [self.tableView reloadData];
        }
    }
}

- (void)updateAlarm:(NSManagedObject*)originalAlarm withAlarm:(NSManagedObject*)newAlarm
{
    NSLog(@"Update!");

    NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
    [context deleteObject:originalAlarm];
    [context insertObject:newAlarm];

    // Save the context.
    NSError *error = nil;
    if (![context save:&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();
    }
}

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
    // The table view should not be re-orderable.
    return NO;
}


#pragma mark -
#pragma mark Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"Did select row");

    if ([self.tableView isEditing])
    {
        // Show editing mode
        NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];

        AddClockNavigationController *viewController = [[AddClockNavigationController alloc] initWithNibName:@"AddClockNavigationController" bundle:nil editManagedObject:managedObject];       
        [[self navigationController] presentModalViewController:viewController animated:YES];
        [viewController release];
    }
}

- (void)cancelAddAlarmView
{
    [self.modalViewController dismissModalViewControllerAnimated:YES];
}

#pragma mark -
#pragma mark Fetched results controller

- (NSFetchedResultsController *)fetchedResultsController {

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

    /*
     Set up the fetched results controller.
     */
    // Create the fetch request for the entity.
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Clocks" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    // Set the batch size to a suitable number.
    [fetchRequest setFetchBatchSize:20];

    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"addDate" ascending:NO];
    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:@"Root"];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;

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

    NSError *error = nil;
    if (![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();
    }

    return fetchedResultsController_;
}    


#pragma mark -
#pragma mark Fetched results controller delegate


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


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

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

        case NSFetchedResultsChangeDelete:
            [self.tableView 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.tableView;

    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.tableView endUpdates];
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:indexPath.section];

    if (indexPath.row < [sectionInfo numberOfObjects])
    {
        return 92;
    }
    else {
        return 40;
    }
}


/*
 // Implementing the above methods to update the table view in response to individual changes may have performance implications if a large number of changes are made simultaneously. If this proves to be an issue, you can instead just implement controllerDidChangeContent: which notifies the delegate that all section and object changes have been processed. 

 - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
 // In the simplest, most efficient, case, reload the table view.
 [self.tableView reloadData];
 }
 */


#pragma mark -
#pragma mark Memory management

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Relinquish ownership any cached data, images, etc that aren't in use.
}


- (void)viewDidUnload {
    // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
    // For example: self.myOutlet = nil;
}

- (void)dealloc {
    [fetchedResultsController_ release];
    [managedObjectContext_ release];

    [locationManager stopUpdatingLocation];
    [locationManager release];

    [super dealloc];
}


@end

EDIT
This is the code of the save button, AddClockNavigationController.m:

- (IBAction)saveAlarm
{
    [self saveTheAlarm];
}

- (void)saveTheAlarm
{
    AddClockViewController *viewController = [navigationController.viewControllers objectAtIndex:0];

    UITableView *alarmTable = viewController.theTable;

    NSIndexPath *textFieldIndexPath = [NSIndexPath indexPathForRow:0 inSection:0];
    UITextField *textField = (UITextField*)[[alarmTable cellForRowAtIndexPath:textFieldIndexPath] accessoryView];

    ClockAppDelegate *appDelegate = (ClockAppDelegate*)[[UIApplication sharedApplication] delegate];

    RootViewController *parentView = [[RootViewController alloc] init];
    [appDelegate addNewAlarmWithTitle:textField.text sound:@"" recurring:[viewController hasRecurring] recurringDays:viewController.recurringDictionary];

    [parentView.tableView reloadData];
    [self.parentViewController dismissModalViewControllerAnimated:YES];

    [parentView release];
}

ClockAppDelegate.m

- (void)addNewAlarmWithTitle:(NSString*)alarmTitle sound:(NSString*)sound recurring:(BOOL)isRecurring recurringDays:(NSDictionary*)days
{
    NSManagedObjectContext *context = managedObjectContext_;
    NSManagedObject *newManagedObject = [NSEntityDescription insertNewObjectForEntityForName:@"Clocks" inManagedObjectContext:context];

    [newManagedObject setValue:alarmTitle forKey:@"title"];
    [newManagedObject setValue:sound forKey:@"alarm"];
    [newManagedObject setValue:[NSNumber numberWithBool:TRUE] forKey:@"active"];
    [newManagedObject setValue:[[NSDate alloc] init] forKey:@"addDate"];

    [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:isRecurring] forKey:@"recurring"];

    NSArray *myKeys = [days allKeys];
    NSArray *sortedKeys = [myKeys sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

    for (id key in sortedKeys) {
        if ([(NSString*)[days objectForKey:key] isEqualToString:@"1"])
        {
            if ([key isEqualToString:@"0"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"mon"];
            }
            else if ([key isEqualToString:@"1"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"tue"];
            }
            else if ([key isEqualToString:@"2"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"wed"];
            }
            else if ([key isEqualToString:@"3"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"thu"];
            }
            else if ([key isEqualToString:@"4"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"fri"];
            }
            else if ([key isEqualToString:@"5"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"sat"];
            }
            else if ([key isEqualToString:@"6"])
            {
                [newManagedObject setPrimitiveValue:[NSNumber numberWithBool:TRUE] forKey:@"sun"];
            }
        }
    }

    // Save the context.
    NSError *error = nil;
    if (![context save:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
}

What is it I am doing wrong?

Best regards,
Paul Peelen

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1 Answer

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  1. Editorial Team
    Editorial Team
    2026-05-20T06:15:59+00:00Added an answer on May 20, 2026 at 6:15 am

    From Core Data Docs

    Managed object invalidated Problem:
    You see an exception that looks
    similar to this example:

    [_assignObject:toPersistentStore:]:
    The NSManagedObject with ID:#### has
    been invalidated. Cause: Either you
    have removed the store for the fault
    you are attempting to fire, or the
    managed object’s context has been sent
    a reset message.

    Remedy: You should discard this
    object. If you add the store again,
    you can try to fetch the object again

    So, basically, you have a reference to managed object that has become disconnected from its store or context.

    I don’t see an obviousl place for this to happen but you are sending a retain message to a managed object in tableView:cellForRowAtIndexPath: here:

    NSManagedObject *managedObject = [[self.fetchedResultsController objectAtIndexPath:indexPath] retain];
    

    … which is dangerous even if you subsequently release it. Never retain managed objects but instead rely on the context to retain it. Otherwise, the context may release the managed object and mark it as invalidated while another object keeps it alive.

    I would suggest going through all your code and finding all places you send a retain to a managed object and remove the unnecessary retain/release code. That will probably resolve the problem.

    If not you need to check that your persistent store is and remains properly assigned to the persistent store coordinator.

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