how to update tableView when insert new data to the relation - core-data

Question

I use 2 entities Person and Event that connected by relation 'events' one to many. in my first table view I have Person's names at the second I have their Events types. I can insert new event to specific person but the problem that the second table view don't update as well. only if I use navigator back to persons and after it go events again I see the changes.
for insert new event I use this method:
- (void) addEventControllerDidSave:(NSString *)typeData{
NSManagedObjectContext* context = [self managedObjectContext];
Event *newEvent = (Event *)[NSEntityDescription insertNewObjectForEntityForName:#"Event" inManagedObjectContext:context];
[newEvent setType:typeData];
[currentPerson addEventsObject:newEvent];
NSError *error;
if (![[self managedObjectContext] save:&error])
{
NSLog(#"Problem saving: %#", [error localizedDescription]);
}
[self dismissViewControllerAnimated:YES completion:nil];
}
how I define the cell:
//create cell use relation
NSArray *eventsArray = [[[[self currentPerson] events] objectEnumerator]allObjects];
Event *newEvent = [eventsArray objectAtIndex:indexPath.row];
[[cell textLabel]setText: [newEvent type]];
update table methods:
- (void) controllerWillChangeContent:(NSFetchedResultsController *)controller{
[[self tableView] beginUpdates];
}
- (void) controllerDidChangeContent:(NSFetchedResultsController *)controller{
[[self tableView] endUpdates];
}
- (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:
{
NSArray *eventsArray = [[[[self currentPerson] events] objectEnumerator]allObjects];
Event *newEvent = [eventsArray objectAtIndex:indexPath.row];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
[[cell textLabel]setText: [newEvent type]];
break;
}
case NSFetchedResultsChangeMove:
{
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
}
default:
break;
}//switch
}
- (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;
default:
break;
}
}
I don't really know how update the tableView correct, I update my first tableView but the second have the problem that I describe early (maybe it because I use relation?)
you can also see my full project until now at the git (maybe it helps):
https://github.com/dennis87/eventCost

Answer 1

The EventsTableController has a fetchResultsController property and corresponding _fetchResultsController instance variable. But this FRC is always nil because it is never allocated + initialized in the EventsTableController.
The update methods controllerWillChangeContent, didChangeObject, controllerDidChangeContent are never called, because you have no FRC with a delegate.
As a workaround, you could add
[self.tableView reloadData];
in addEventControllerDidSave, then new entries will be visible immediately.
But the real solution would be to init and use a FRC, as you have already done in the NamesTableController. Then new events would be displayed automatically.
Creating a fetched results controller that fetches all events for the current person would look like this (this is your code from the NamesTableController, modified for use in the EventsTableController):
-(NSFetchedResultsController *) fetchResultsController{
if (_fetchResultsController != nil) {
return _fetchResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Event"
inManagedObjectContext:[self managedObjectContext]];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"person = %#", self.currentPerson];
[fetchRequest setPredicate:predicate];
NSSortDescriptor *sort = [[NSSortDescriptor alloc]initWithKey:#"type" ascending:YES];
NSArray *sortArray = [[NSArray alloc]initWithObjects:sort, nil];
[fetchRequest setSortDescriptors:sortArray];
_fetchResultsController = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest
managedObjectContext:[self managedObjectContext]
sectionNameKeyPath:nil
cacheName:nil];
_fetchResultsController.delegate = self;
return _fetchResultsController;
}