Show sections with core data - ios

Question

I want to code a todo app and display 2 sections. 1 for entrys, that have to be done and 1 for already done things.
I want something like that:
Things not done yet
Todo 1
Todo 2
Things already done
Todo 3
Todo 4
At the moment I have 1 section for the undone todos.
My code for the table view at the moment looks like this
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
NSArray *array = [[NSArray alloc] initWithObjects:#"To do",#"done",nil];
return [array objectAtIndex:section];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];
return [sectionInfo numberOfObjects];
}
And my code for the fetchedresultscontroller looks like this:
- (NSFetchedResultsController *)fetchedResultsController
{
if (_fetchedResultsController != nil) {
return _fetchedResultsController;
}
NSManagedObjectContext* context = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription* entity = [NSEntityDescription entityForName:#"Todo" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"timestamp" ascending:YES];
NSArray *sortDescriptors = #[sortDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"done == %#", #(NO)];
[fetchRequest setPredicate:predicate];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:#"done" cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return _fetchedResultsController;
}
Objects with the key "NO" are not done and with the key "YES" are done. But I don't know how to display both values in different sections.
Edit
I found the solution to my problem…
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:#"done" cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
That solved this problem. But now sometimes an undone item shows up at done.
Or if there are two done items they appear under "Todo"
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
NSArray *array = [[NSArray alloc] initWithObjects:#"Todo",#"Done",nil];
return [array objectAtIndex:section];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];
return [sectionInfo numberOfObjects];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
[self configureCell:cell atIndexPath:indexPath];
return cell;
}
Thats my actual code for that…
Now it looks like that. Undone todo unchecked, done todo checked. http://img.xnmn.de/i/2353ad.png
But if I check undone todo as done, they both appear at "todo" http://img.xnmn.de/i/5edff4.png

Answer 1

You're code looks almost right. Since you set the sectionKeyPath to "done", the fetched results controller will automatically create the sections for you. You could add another sort descriptor for the "done" attribute to sort the entries according to their section.
What you have to do is to remove the NSPredicate. In you current code, you're filtering out all entries with "done == YES", but since you have your two sections, you want the results controller to return all entries.
So basically you just need to remove the
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"done == %#", #(NO)];
[fetchRequest setPredicate:predicate];
Of course you'd also have to implement the – tableView:cellForRowAtIndexPath: method

Answer 2

If i get your Code right you already created the section which is fine.
- (UITableViewCell *)tableView:(UITableView *)inTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *identifier = #"Entry";
UITableViewCell *cell = [inTableView dequeueReusableCellWithIdentifier:identifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:identifier];
}
YourObject *cellEntry = [_fetchedResultsController objectAtIndexPath:indexPath];
//init cell
}
This should choose the right entry for the right section otherwise the line where you set the section is wrong.
The index path chooses the right section.