Question

I have the standard fetchedResultsController method and delegate methods in my viewController but they are not being called. I tested this by putting an NSLog in this method and the console never shows this.

I made sure to add FetchedResultsController delegate to .h and .m.

Any ideas why?

Interface

 @interface LogViewController : UIViewController <NSFetchedResultsControllerDelegate, UITableViewDelegate, UITableViewDataSource>

@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
@property (nonatomic, retain) NSArray *logArray;
@property (nonatomic, retain) UIImageView *imageView;
@property (nonatomic, retain) Session *session;

@property (nonatomic, retain) IBOutlet UITableView *logTableView;

@end

Implementation

#import "LogViewController.h"

@implementation LogViewController

@synthesize fetchedResultsController = __fetchedResultsController;
@synthesize managedObjectContext;
@synthesize logArray;
@synthesize logTableView;
@synthesize imageView;
@synthesize session;

- (void)dealloc
{
    [logArray release];
    [logTableView release];
    [session release];
    [__fetchedResultsController release];
    [managedObjectContext release];
    [super dealloc];
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationItem.title = @"Log";
    logTableView.backgroundColor = [UIColor clearColor];
    logTableView.separatorColor = [UIColor blackColor];
    self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:24/255.0 green:83/255.0 blue:170/255.0 alpha:1.0];
    self.logArray = [[NSArray alloc]initWithObjects:@"Today's Workout", @"Last Workout", @"Past Week", @"Past Month", @"All Workouts", nil];

    if (managedObjectContext == nil)
    {
        self.managedObjectContext = [(CurlAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
    }
}

- (void)viewDidUnload
{
    self.logArray = nil;
    self.logTableView = nil;
    [super viewDidUnload];
}

#pragma mark - Table view data source


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

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.logArray count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    TDBadgedCell *cell = [[[TDBadgedCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];

    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier] autorelease];
    }
    cell.textLabel.textColor = [UIColor blackColor];
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    cell.textLabel.text = [logArray objectAtIndex:indexPath.row];
    cell.backgroundColor = [UIColor clearColor];
    UIImageView *myImageView = nil;
    if (indexPath.row == 0)
    {
        myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_top.png"]];
    }
    else if (indexPath.row == 4)
    {
        myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_bottom.png"]];
    }
    else
    {
        myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_middle.png"]];
    }
    [cell setBackgroundView:myImageView];
    [myImageView release];

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MMM d, y"];
    NSDate *date = nil;
    if (indexPath.row == 0)
    {
        date = [NSDate date];
        NSString *dateString = [dateFormatter stringFromDate:date];
        cell.badgeString = dateString;
    }
    else if (indexPath.row == 1)
    {
        self.session = [[__fetchedResultsController fetchedObjects]lastObject];
        NSDate *date = self.session.timeStamp;
        NSString *dateString = [dateFormatter stringFromDate:date];
        cell.badgeString = dateString;
    }
    else if (indexPath.row > 1)
    {
        cell.badgeString = [NSString stringWithFormat:@"%i", [[__fetchedResultsController fetchedObjects]count]];
    }
    cell.badgeColor = [UIColor colorWithRed:24/255.0 green:83/255.0 blue:170/255.0 alpha:1.0];
    [dateFormatter release];

    return cell;
}

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
// [cell setBackgroundColor:[UIColor colorWithRed:209/255.0 green:209/255.0 blue:209/255.0 alpha:1.0]];
}

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [tableView deselectRowAtIndexPath:indexPath animated:YES];

    if (indexPath.row == 0 || indexPath.row == 1)
    {
        SessionViewController *detailViewController = [[SessionViewController alloc] initWithNibName:@"SessionViewController" bundle:nil];
        detailViewController.title = [logArray objectAtIndex: indexPath.row];
        [self.navigationController pushViewController:detailViewController animated:YES];
        [detailViewController release];
    }
    else
    {
        LogResultsViewController *detailViewController = [[LogResultsViewController alloc] initWithNibName:@"LogResultsTableViewController" bundle:nil];
        detailViewController.title = [logArray objectAtIndex: indexPath.row];
        [self.navigationController pushViewController:detailViewController animated:YES];
        [detailViewController release];
    }
}

#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:@"Session" 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:@"timeStamp" 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: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();
    }
    return __fetchedResultsController;
    NSLog(@"Number of Objects = %i",
          [[__fetchedResultsController fetchedObjects] count]);

}

#pragma mark - Fetched results controller delegate


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

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

        case NSFetchedResultsChangeDelete:
            [self.logTableView 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.logTableView;

    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.logTableView endUpdates];
}

@end

Answer 1

replace calls like this

self.session = [[__fetchedResultsController fetchedObjects]lastObject];

with this

self.session = [[self.fetchedResultsController fetchedObjects]lastObject];

I.E. Use the getter that lazily loads the NSFetchedResultsController.
If you use lazy loading you have to use the getter, because the instance variable will stay nil if you never invoke the getter that creates the object.