Editing specific CoreData entries - ios

Question

Once again, since Core Data is new to me, I need assistance. Basically, I need to edit a specific Core Data object from a view outside the tableview, save it, and reload the tableview. I can manage reloading the tableview, but I cannot figure out how to find the specific Core Data object for that indexPath entry. I don't have any code because I cannot find anything to suit my purpose.
Detail (Editor)
-(IBAction)cancel:(id)sender{
NSLog(#"Sent!");
// [self dismissViewControllerAnimated:YES completion:nil];
// [self.view.superview removeFromSuperview];
OweDetails *details = info.details;
[info setValue:oField.text forKey:#"name"];
info.name = oField.text;
[UIView animateWithDuration:0.5
delay:1.0
options: UIViewAnimationOptionCurveEaseIn
animations:^{
self.master = [[MasterViewController alloc]init];
[self dismissSemiModalViewController:self];
[self.master.tableView reloadData];
}
completion:^(BOOL finished){
NSLog(#"Done!");
}];
}
Master (TableView)
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(#"I tapped myself!");
OweInfo *info = [_fetchedResultsController objectAtIndexPath:indexPath];
self.tdModal = [[TDSemiModalViewController alloc]init];
[tableView deselectRowAtIndexPath:indexPath animated:YES];
FooterViewController *fvc = [[FooterViewController alloc]init];
OweDetails *details = info.details;
[self.tdModal setDetailItem:info.name];
[self.tdModal setMoneyItem:details.money];
// [self.view addSubview:test.view];
self.tdModal.managedObjectContext = self.managedObjectContext;
self.tdModal.managedObjectContext = self.managedObjectContext;
OweInfo *info2 = (OweInfo *)[nameArray objectAtIndex:indexPath.row];
self.tdModal.info = info2;
[self presentSemiModalViewController:self.tdModal];
}

Answer 1

If you're using an NSFetchedResultsController, ask it for the objectAtIndexPath:.

Answer 2

AppDelegate* appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext* context = [appDelegate managedObjectContext];
NSEntityDescription *entity = [NSEntityDescription
entityForName:#"YOUR_ENTITY_NAME" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SOME_PREDICATE_USED_TO_UNIQUELY_IDENTIFY_YOUR_INDEXPATH ==%#", #"VALUE"];
[fetchRequest setPredicate:predicate];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entity];
[request setPredicate:predicate];
NSError* error;
NSArray* array = [context executeFetchRequest:request error:&error];
if (error)
{
NSLog(#"Error fetching data. %#", error);
return nil;
}
if (array.count != 1)
{
NSLog(#"Invalid number (%d) of objects found", array.count);
return nil;
}
return [array objectAtIndex:0];
Edit: This is in response to you asking about more details.
The code above can be its own function. I will give you a simple example of how you can use it.
-- In the VC where you have the table and are displaying the data
1: Let us assume your entity is called MyEntity and that it has an integer unique identifier field called myEntityUniqueId.
2: In your cellForRowAtIndexPath, you would write:
cell.tag = myCurrentEntity.myEntityUniqueId
-- Now lets go to your other VC where you want to retrieve the instance of MyEntity represented by the cell that was tapped.
1: Write the function:
-(void) findMyEntityForId:(int) tappedUniqueId
{
AppDelegate* appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
NSManagedObjectContext* context = [appDelegate managedObjectContext];
NSEntityDescription *entity = [NSEntityDescription
entityForName:#"MyEntity" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"myEntityUniqueId ==%d", tappedUniqueId];
[fetchRequest setPredicate:predicate];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entity];
[request setPredicate:predicate];
NSError* error;
NSArray* array = [context executeFetchRequest:request error:&error];
if (error)
{
NSLog(#"Error fetching data. %#", error);
return;
}
if (array.count != 1)
{
NSLog(#"Invalid number (%d) of objects found", array.count);
return;
}
MyEntity* foundResult = [array objectAtIndex:0]; // <-- This is the instance you are looking for.
}
2: Now call the above function with the correct argument.
I haven't tested the code but it should be fine.