Issue with deleting rows after adding section header to uitableview - ios

Question

Before adding section headers to one of my tables in my app, I was able to delete rows using the commitEditingStyle function without any issues. I decided to implement section headers to make it easier for the user to view items added to the table by date. This functionality works fine. I was having an issue with deleting rows after implementing the section headers but thanks to help from the good folks on stackoverflow the problem was partially resolved. After some testing I've realized that if the rows are in the same section and I try to delete more than one row in sequence beginning with the top row in the section, the top row deletes fine but trying to delete the second row causes the app to crash. If I delete all rows in sequence other than the first row and then delete the first row last, it works fine. Xcode doesn't indicate why it crashes in the debug log.
Here is the code for the cellForRowAtIndexPath function:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
AgendaCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[AgendaCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
NSString *strDate = [dateArray objectAtIndex:indexPath.section];
NSMutableArray *dateSection = [tempDict objectForKey:strDate];
NSManagedObject *object = [dateSection objectAtIndex:indexPath.row];
cell.sessionNameLabel.text = [object valueForKey:#"sessionname"];
cell.sessionNameLabel.textColor = [UIColor blueColor];
cell.sessionDateLabel.text = [object valueForKey:#"sessiondate"];
cell.sessionDateLabel.textColor = [UIColor brownColor];
cell.sessionTimeLabel.text = [object valueForKey:#"sessiontime"];
cell.sessionTimeLabel.textColor = [UIColor brownColor];
return cell;
}
Here is the code for my table refresh function:
- (void) refreshTable
{
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Sessnotes" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setPredicate:[NSPredicate predicateWithFormat:#"agenda == 'Yes'"]];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"sessiondate" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSArray *results = [self.managedObjectContext executeFetchRequest:fetchRequest error:nil];
[self.refreshControl endRefreshing];
self.objects = results;
if (results.count == 0) {
NSString *message = #"You have not added any sessions to your planner.";
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:#"Notification"
message:message
delegate:self
cancelButtonTitle:#"Ok"
otherButtonTitles:nil,nil];
[alertView show];
}
else if (results.count > 0){
tempDict = nil;
tempDict = [[NSMutableDictionary alloc] init];
NSString *strPrevDate= [[results objectAtIndex:0] valueForKey:#"sessiondate"];
NSLog(#"strPrevDate value is: %#", strPrevDate);
NSString *strCurrDate = nil;
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
//Add the Similar Date data in An Array then add this array to Dictionary
//With date name as a Key. It helps to easily create section in table.
for(int i=0; i< [results count]; i++)
{
strCurrDate = [[results objectAtIndex:i] valueForKey:#"sessiondate"];
if ([strCurrDate isEqualToString:strPrevDate])
{
[tempArray addObject:[results objectAtIndex:i]];
}
else
{
[tempDict setValue:[tempArray copy] forKey:strPrevDate];
strPrevDate = strCurrDate;
[tempArray removeAllObjects];
[tempArray addObject:[results objectAtIndex:i]];
}
}
//Set the last date array in dictionary
[tempDict setValue:[tempArray copy] forKey:strPrevDate];
NSArray *tArray = [tempDict allKeys];
//Sort the array in ascending order
dateArray = [tArray sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
}
[self.tableView reloadData];
}
Here is the code for the commitEditingStyle function:
- (void)tableView:(UITableView *)tableView commitEditingStyle: (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
//add code here for when you hit delete
NSManagedObject *object = [self.objects objectAtIndex:indexPath.row];
NSManagedObjectContext *context = [self managedObjectContext];
[context deleteObject:[context objectWithID:[object objectID]]];
NSError *error = nil;
// Save the object to persistent store
if (![context save:&error]) {
NSLog(#"Can't Save! %# %#", error, [error localizedDescription]);
}
NSMutableArray *array = [self.objects mutableCopy];
[array removeObjectAtIndex:indexPath.row];
self.objects = array;
[tableView reloadData];
}
}

Answer 1

A couple things up front. I wouldn't make fetch requests everytime you want to reload the tableview. You should look at NSFetchedResultsController. It will automatically bind data to your tableview and do the refreshes for you based on updates coming from either the same NSManagedObjectContexts or messages about updates from other contexts and batch them for you as well.
To answer your original question. I would try to remove the object from the array first and then delete the NSManagedObject and then you can use some tableview trickery:
NSManagedObject *managedObject = self.array[indexPath.row];
[self.array removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation: UITableViewRowAnimationAutomatic];
[context deleteObject:managedObject];
I could be wrong but it's possible you're failing to fullfil a fault. Hope that helps.