Question

I’m working on App with coreData and i get an error that i can’t understand: In a custom init whether i define NSFetchedResultController with “self.controller = new_controller” all works correctly, if i define only “controller = new_controller” (without self), error “The NSManagedObject has been invalidated” occur after 2 loops for the situation described in this image:

Application parts interested in this error is here described:

• A Table with a list of Months (Class MonthListVC, step 1 in the image). Where
  sections describe Month (like April
  2011) and the unique Row for any
  section present data (that are sum
  from transactions happened during the
  month).

• Selecting one of these Row a next
  Table is pushed in navigation
  controller (Class WeekTVC, step 2 in the image), this table presents
  detail for every weeks for selected month. Here section title has format “week beginning – week end”, and the unique row for the section is a sum of transactions for the week.

• A NSManagedObjectContext is passed via a custom init method (check the code)

• every data for these tables are managed with
  NSFetchedResultController.

Here the code for selection on first Table (MonthListVC)

 -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{

    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.controller sections] objectAtIndex:indexPath.section];

    // get the first object for this section and get its date.
    NSDate *datepoint = [[[sectionInfo objects]objectAtIndex:0] date];

    //Create next Controller and push it into Navigation
    WeeksTVC *weeksTVC = (WeeksTVC*)[[WeeksTVC alloc] initWithContext:self.context datepoint:datepoint withTitle: [sectionInfo name] ];

    [self.navigationController pushViewController:weeksTVC animated:YES];

    [weeksTVC release];
}

And here the code for WeeksTVC custom init method, where i define “self.controller = …” and where i get the problem whether i write only “controller = …”.
“controller” is a synthesized property.

-(WeeksTVC *)initWithContext:(NSManagedObjectContext *)n_context datepoint:(NSDate*)n_datePoint withTitle:(NSString*) stringTitle{   
    self = [self init];

    if(self !=nil){ 

        self.title =  [NSString stringWithFormat:@"History (%@)",stringTitle];

        //Back button setup
        UIBarButtonItem *barButton = [[UIBarButtonItem alloc] init];
        barButton.title = @"Back";
        self.navigationItem.backBarButtonItem = barButton; 

        //datePoint = n_datePoint;
        self.context = n_context;

        //Get Begin and End week information for this datePoint
        NSDate *startDay = [[CommonHelper weekInfoFromData:[CommonHelper firstDayOfMonthForDate:n_datePoint]] objectForKey:@"begin"];
        NSDate *endDay = [[CommonHelper weekInfoFromData:[CommonHelper lastDayOfMonthForDate:n_datePoint]] objectForKey:@"end"];

        //Manage Request
        NSFetchRequest *request = [[NSFetchRequest alloc]init];
        request.entity = [NSEntityDescription entityForName:@"Transactions" inManagedObjectContext:self.context];
        request.predicate = [NSPredicate predicateWithFormat:@"(date >= %@) && (date <= %@)",startDay,endDay]; 
        NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"date" ascending:NO];
        NSArray *sortDescs = [NSArray arrayWithObjects:sort,nil];
        request.sortDescriptors = sortDescs;

        "HERE THE PROBLEM WITH SELF***********************************************"
        //Manage NSResultFetchedController 
        self.controller = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:self.context sectionNameKeyPath:@"byWeek" cacheName:nil];
        self.controller.delegate = self;
        NSError *error = nil;

        //Fetch
        [self.controller performFetch:&error];
        "END OF PROBLEM***********************************************************"

        [request release];  
        [barButton release];
    }
    return self;
}

I report also dealloc method for WeeksTVC, i found that if i don’t release context and controller in this method… no error occur also if i write in init method “controller = ” and not “self.controller = “

- (void)dealloc {
    //[self.datePoint release];
    [self.controller release];
    [self.context release];
    [super dealloc];
}

Why self.controller and controller are so different in this case ???
In init method i ever write ivar without self -.-‘

Answer 1

In custo init method for WeeksTVC i wrote

self = [self init];

and not

self = [super init];

This cause the problem… but i’m curious to understand what happen exactly…