Core Data update in UITextField delegate causes crash - ios

Question

I am working on app and simply editing the cell text field and at finish editing, I am trying to update coredata but app get stack and some time it give SIGSTOP and sometime it says unable to allocate more memory kinda error, please help me with this.
- (void)textFieldDidEndEditing:(UITextField *)textField
{
if ((textField.tag - 999) > 0) {
NSArray *visible = [self.productTable indexPathsForVisibleRows];
UITableViewCell* cell = [self.productTable cellForRowAtIndexPath:[visible objectAtIndex:(textField.tag - 999)]];
for (UIView* subview in [cell.contentView subviews]) {
if ([subview isKindOfClass:[UITextField class]]) {
textField = (UITextField*)subview;
Product* myProduct = (Product*)[self.productArray objectAtIndex:(textField.tag - 1000)];
[myProduct setValue:[NSNumber numberWithFloat:[textField.text floatValue]] forKey:#"quantity"];
[myProduct setValue:[NSNumber numberWithFloat:[myProduct.quantity floatValue] * [myProduct.rate floatValue]] forKey:#"amount"];
NSLog(#"Product %#", myProduct);
NSError *error; if (![self.managedObjectContext save:&error]) {
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
}
}

Answer 1

It seems that your subview loop is really not necessary.
But already your check by visible cells seems flawed.
You get the index paths of all visible cells.
You pick one of these index paths based on the text field's tag.
--> This has unpredictable results. If the table view has scrolled, the exact index of your cell in the array of visible cells is not clear. If the cell has scrolled off the screen, the array will be empty and you get a crash.
Why so complicated?
Isn't the text field you need exactly the text field that is passed into the delegate method?
All you need is this:
UITableViewCell *cell = (UITableViewCell*) textField.superview.superview;
Product *myProduct = [self.fetchedResultsController objectAtIndexPath:
[self.tableView indexPathForCell:cell]];
You are using a NSFetchedResultsController, right? If not, you definitely should!