How to present an empty cell? - ios

Question

My task is simple basically for most of you, but obviously im doing something wrong here.
I have a two table view controllers that I want to populate their cells based on some object status. Im working with core data so also doing fetchResultController too.
in one of the view controllers I can change the status of the cell object (not the actual cell, the object that is populating the cell), and whenever that happened I want to delete this cell from the table view. In that view controller I want to present only the cells that the object that is populating them have the status = 0. but I dont want to delete the ones that was deleted, just to change their status to 1, and then in some other view controller to present them if they have the status = 1.
So what im doing is:
Whenever the commitEditingStyle is getting called:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
Target *target = [self.fetchedResultController objectAtIndexPath:indexPath];
target.status = #1;
}
if ([_delegate respondsToSelector:#selector(didDeleteObject)]) {
[self fetchData];
[_delegate didDeleteObject];
}
}
Now what I had in mind is in the cellForRowAtIndexPath method to add a condition when im returning a cell like this:
if ([target.status isEqual:#0]) {
return cell;
}
return NULL;
}
since I want to present only the cells that have the status 0...
So now obviously I cannot enter this table view because I have to return a cell in this method and not done, how can i just say that if the statues of the object target is different than 1 so dont present the cell?
other code solutions will be great too :)
thanks!!!

Answer 1

You should be able to filter out fetch request with a predicate
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:#"Target"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"status == %#", [NSNumber numberWithBool:NO]];
[fetchRequest setPredicate:predicate];
When you set your status attribute to 1, FetchedResultsController will automatically delete cell from the tableView, but the object will not get deleted. You don't have to do anything in the cellForRowAtIndexPath. And in your other tableView, set the predicate to only fetch status == 1.
Also, make sure to save the managedObjectContext when you change the attribute's value.
Target *target = [self.fetchedResultController objectAtIndexPath:indexPath];
target.status = #1;
NSError *error = nil;
if (![self.managedObjectContext save:&error]) {
NSLog(#"Save Failed! %# %#", error, [error localizedDescription]);
}

Answer 2

You can't do it in this way.
You have to set a dynamic numberOfRowsInSection:, depending on how many Target has status property equal to #0
So, in tableView:cellForRowAtIndexPath: you will return the cell only if the status is #0.
For me is better if you split the dataSource in dataSource with target.status = #0 and others.
A right way is this
// This is the point where you have an update dataSource array (not splitted)
updatedDatas = [Manager getLatestData];
if (dataSource.count > 0)
[dataSource removeAllObjects];
[updatedDatas enumerateObjectsUsingBlock:^(Target *obj, NSUInteger idx, BOOL *stop) {
if ([obj.status integerValue] == 0)
[dataSource addObject: obj];
}];
updatedDatas = nil;
// This is the numberOfRowsInSection:
- (NSInterger)numberOfRowsInSection:(NSInteger)section{
return dataSource.count;
}
In the tableView:cellForRowAtIndexPath: you will now use the dataSource NSMutableArray with a simple objectAtIndex: to access the correct element