Problem with objective-c troubleShooting

Question

Hi there,
i'm all new to mac & iOS developement and am getting startet by working throught what appeared to be a great book "Einstieg in Objective-C 2.0 and Cocoa inkl iPhone programming".
what im doing right now is creating an Weblog App for the iPhone by following stepBy step coding and interface instructions by this book.
problem: everything seems to work just fine, i can compile and everything. but one funktion does not work which is creating a new article.
the errorcode looks like that:
[phone]:59:28.775 WeblogClientTouch[12682:207] Fehler beim Anlegen eines neuen Artikels+
and is produced by an NSLog:
if (![managedObjectContext save:&error]) {
NSLog(@"Fehler beim Anlegen eines neuen Artikels");
so apparently the saving of a new entity 'article' does not work. here some code snippets that might help, first the function that creates a new article in which the error occurs:
- (IBAction)neuerArtikel
//erzeuge artikel
NSEntityDescription *artikelDescription = [[fetchedResultsController fetchRequest]entity];
NSManagedObject *newArtikel = [NSEntityDescription insertNewObjectForEntityForName:[artikelDescription name]
inManagedObjectContext:managedObjectContext];
//befülle artikel mit standardwerten
[newArtikel setValue:NSLocalizedString(@"Neuer Artikel", nil)
forKey:@"titel"];
[newArtikel setValue:[NSDate date] forKey:@"datum"];
[newArtikel setValue:@"Markus" forKey:@"autor"];
//speichere artikel
NSError *error;
if (![managedObjectContext save:&error]) {
NSLog(@"Fehler beim Anlegen eines neuen Artikels");
//Tableview aktualisieren
[self.tableView reloadData];
in my datamodel i have only one entity named "Artikel" with the attributes: autor, titel, datum, inhalt.
i would be very glad about some tips, because i've been trying to solve the problem for nearly 3 hours now and i dont think it can be that tricky..
Message was edited by: sfluecki
Message was edited by: sfluecki

Answer 1

allRight.
i got it working so far that there's no more errors.
--> i can now klick on 'new article' without any errors, but my tableView does not show the new allocated articles
--> after i restart the app (rebuild, reRun in simulator) the previously added articles are showing in the tableView.
--> somehow my tableView does just update itself whilst starting the app.
in the end of the 'addNewArticle' function i have the following:
[self.tableView reloadData];
the tableView itself is defined by the following:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
NSArray *sections = [fetchedResultsController sections];
NSUInteger count = 0;
if ([sections count]) {
id <NSFetchedResultsSectionInfo> sectionInfo = [sections objectAtIndex:section];
count = [sectionInfo numberOfObjects];
return count;
and
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
static NSString *CellIdentifier = @"Cell";
//Zelle aus dem Cache holen oder erzeugen wenn nicht orhanden
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:CellIdentifier] autorelease];
NSManagedObject *artikel = [fetchedResultsController objectAtIndexPath:indexPath];
//Titel als haupttext der zelle
cell.textLabel.text= [artikel valueForKey:@"titel"];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
//Autor und Name als Detailtext der Zelle
NSDateFormatter *dateFormatter = [NSDateFormatter new];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *dateString = [dateFormatter stringFromDate:[artikel valueForKey:@"datum"]];
cell.detailTextLabel.text = [NSString stringWithFormat:NSLocalizedString(@"%@ am %@",nil), [artikel valueForKey:@"autor"], dateString];
[dateFormatter release];
return cell;
whilst the function fetchedResultsController looks like this.
- (NSFetchedResultsController *)fetchedResultsController
if (fetchedResultsController != nil)
return fetchedResultsController;
//FetchRequest initialisieren
NSFetchRequest *fetchedRequest = [NSFetchRequest new];
NSEntityDescription *artikelDescription = [NSEntityDescription entityForName:@"Artikel"
inManagedObjectContext:managedObjectContext];
[fetchedRequest setEntity:artikelDescription];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"datum" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc]initWithObjects:sortDescriptor, nil];
[fetchedRequest setSortDescriptors:sortDescriptors];
//FetchedResultsController initialisieren
fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:fetchedRequest
managedObjectContext:managedObjectContext
sectionNameKeyPath:nil
cacheName:@"Overview" ];
fetchedResultsController.delegate = self;
//aufräumen
[fetchedRequest release];
[sortDescriptor release];
[sortDescriptors release];
return fetchedResultsController;
i'm sorry to bother you with that lot of code.. but i'm stuck here since now 8h,
and wouldnt probably be any step further without your help in the first place,
so thanks a lot for the first inputs =)