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PONSFetchedResultsController Delegate is removing and object from the results controller when I select a tableview row
 

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  1. PONSFetchedResultsController Delegate is removing and object from the results controller when I select a tableview row
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    <p>Core Data Master-Detail Application. </p> <p>When my <code>tableView</code> loads it presents a view with <code>UIButtons</code> to select what category of items you want to view. The <code>IBAction</code> for the buttons takes that category and creates a <code>NSFetchedResultsController</code> with a <code>NSPredicate</code> based on that category. The only difference between the buttons is, 2 of the 8 buttons sets the <code>predicate</code> to grab all the objects based on a <code>BOOL</code>/<code>NSNumber</code> value that is set as a property on the object. The other 6 buttons grab all the objects based on their "category" which again is a <code>NSString</code> property set on the object </p> <p><strong>My Issue:</strong></p> <p>When I select any of the buttons that grab the objects by the category (<code>NSString</code>) everything works fine. It loads the tableview with all the correct objects I select a row the delegate method <code>-controller didChangeObject</code> is called with the type <code>NSFetchedResultsChangeUpdate</code> I pass in object to the <code>DetailViewController</code> and all is well.</p> <p>When I select any of the buttons that grab the objects by the <code>BOOL</code> value everything appears to work fine. The tableview loads all the correct objects and displays properly. <strong>However,</strong> when I select a row the delegate method <code>-controller didChangeObject</code> is called with the type <code>NSFetchedResultsChangeDelete</code> and my object is removed from the tableview. The <code>DetailViewController</code> is pushed on to the stack and displays all the information correctly.</p> <p>I don't know why it is removing my object from the fetched results, it makes no sense to me. Because there is nothing different that I am doing besides the fetch by <code>BOOL</code> property rather than the <code>NSString</code> property.</p> <p>Also; when I select a row I change a property value on the object in the <code>-tableview didSelectRowAtIndexPath</code>. The property I change is just a BOOL value to track if the item has been viewed or not yet. When I remove this line of code that changes this property value everything works fine. I don't understand why this line of code doesn't effect the other categories, only the category that grabs from the <code>BOOL</code> property.</p> <p><strong>CODE:</strong> <strong>IBAction for Categories buttons</strong></p> <pre><code>-(IBAction)goToPage:(id)sender { BOOL wishList = NO; BOOL cellar = NO; if ((UIButton*)sender == americanButton) { selectedCategory = @"american"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == canadianButton) { selectedCategory = @"canadian"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == irishButton) { selectedCategory = @"irish"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == japaneseButton) { selectedCategory = @"japanese"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == scottishButton) { selectedCategory = @"scotch"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == verticalsButton) { selectedCategory = @"verticals"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == otherButton) { selectedCategory = @"other"; selectedSubCategory = nil; wishList = NO; cellar = NO; } else if ((UIButton*)sender == wishListButton) { selectedSubCategory = @"wishlist"; selectedCategory = nil; wishList = YES; cellar = NO; } else if ((UIButton*)sender == cellarButton) { selectedSubCategory = @"cellar"; selectedCategory = nil; wishList = NO; cellar = YES; } if (wishList == YES) { [self fetchMyWhiskiesFromCategory:@"1" andResetFetchResultsController:YES withAttribute:@"wishlist"]; } else if (cellar == YES) { [self fetchMyWhiskiesFromCategory:@"1" andResetFetchResultsController:YES withAttribute:@"mycellar"]; } else { [self fetchMyWhiskiesFromCategory:selectedCategory andResetFetchResultsController:YES withAttribute:@"category"]; } } - (void)fetchMyWhiskiesFromCategory:(NSString *)category andResetFetchResultsController:(BOOL)reset withAttribute:(NSString *)attribute { NSError *error = nil; NSFetchedResultsController *resultsController = [self fetchedResultsControllerWithCategory:category andResetFetchResultsController:reset withAttribute:attribute]; if (![resultsController performFetch:&amp;error]) { NSLog(@"Error! %@", error); } } - (NSFetchedResultsController *)fetchedResultsControllerWithCategory:(NSString *)category andResetFetchResultsController:(BOOL)reset withAttribute:(NSString *)attribute { if (reset == YES) { // If asking for new results controller with new category NSLog(@"Reset results"); self.fetchedResultsController = nil; _fetchedResultsController = nil; } if (_fetchedResultsController != nil) { //NSLog(@"returned Old Controller"); return _fetchedResultsController; } NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]init]; //Entity NSEntityDescription *entity = [NSEntityDescription entityForName:@"Whisky" inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entity]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K == %@",attribute, category]; [fetchRequest setPredicate:predicate]; //Sort all entities by name property (whisky name) NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name"ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; //Create FetchedResultsController organizing by sections of first letter of name _fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"name.stringGroupByFirstInitial" cacheName:nil]; //name.stringGroupByFirstInitial _fetchedResultsController.delegate = self; return _fetchedResultsController; } </code></pre> <p><strong>didSelectRow</strong></p> <pre><code>- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { if (!self.detailViewController) { self.detailViewController = [[DetailViewController alloc] initWithNibName:@"DetailViewController" bundle:nil]; } Whisky *whisky = [self.fetchedResultsController objectAtIndexPath:indexPath]; [whisky setIsNew:[NSNumber numberWithBool:NO]]; self.detailViewController.managedObjectContext = self.managedObjectContext; self.detailViewController.whisky = whisky; [self.navigationController pushViewController:self.detailViewController animated:YES]; } </code></pre> <p><strong>NSFetchedResultsController Delegates</strong></p> <pre><code>- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller { [self.tableView beginUpdates]; } - (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id &lt;NSFetchedResultsSectionInfo&gt;)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type { switch(type) { case NSFetchedResultsChangeInsert: [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"didChangeSection - ChangeInsert"); break; case NSFetchedResultsChangeDelete: [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"didChangeSection - ChangeDelete"); 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:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"didChangeObject - ChangeInsert"); break; case NSFetchedResultsChangeDelete: [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"didChangeObject - ChangeDelete"); break; case NSFetchedResultsChangeUpdate: [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath]; NSLog(@"didChangeObject - ChangeUpdate"); break; case NSFetchedResultsChangeMove: [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade]; [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade]; NSLog(@"didChangeObject - ChangeMove"); break; } } - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { [self.tableView endUpdates]; } </code></pre>
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    1. USiRebel_85
    1. USiRebel_85
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    1. COShow the code for the fetch requests and the cell selection.
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      1. PONSFetchedResultsController Delegate is removing and object from the results controller when I select a tableview row
      1. USWain
    2. CO@Wain let me know if you need anymore code.
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      1. PONSFetchedResultsController Delegate is removing and object from the results controller when I select a tableview row
      1. USiRebel_85
    3. COAre your attributes actually BOOLs in the model?
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      1. PONSFetchedResultsController Delegate is removing and object from the results controller when I select a tableview row
      1. USWain
 

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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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