NSMutableSet Core Data

geiger10d · July 2012

I am using core data and set up a one to many relationship for one of my entities. I have two entities. "Team" and "Player" I am trying to add an NSMutableSet of players to the team.

Below is how I am attempting to add a player to the team.


    -(void)addPlayerButton {
    
    [_tempSet addObject:@\"\"];
    
    NSLog(@\"number of cells in _tempSet is:%i\",[_tempSet count]);
    
    [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:1]  withRowAnimation:UITableViewRowAnimationFade]; 
    
    }

This is how I am saving


    -(void)saveButtonWasPressed {
    
    self.team =[NSEntityDescription insertNewObjectForEntityForName:@\"Team\" inManagedObjectContext:self.managedObjectContext];
  
    self.player = [NSEntityDescription insertNewObjectForEntityForName:@\"Player\" inManagedObjectContext:self.managedObjectContext];
    [team addPlayersObject:player];
    
    team.schoolName = _schoolName.text;
    team.teamName = _teamName.text;
    team.teamID = _teamName.text;
    team.season =  _season.text;
    team.headCoach = _headCoach.text;
    team.astCoach = _assistantCoach.text;
    
    player.firstName = cell.playerFirstName.text;
    player.lastName = cell.playerLastName.text;
    player.number  = cell.playerNumber.text;
    
    [self.team addPlayers:_tempSet];

    
    [self.managedObjectContext save:nil];
    [self.navigationController popViewControllerAnimated:YES];    
}

There are two things going wrong, one, the _tempSet only adds one object and can not add anymore. and the second crashes when I click save right before the line [self.team addPlayers:_tempSet]; With the error [__NSCFConstantString _isKindOfEntity:]: unrecognized selector sent to instance 0xd7cd8'

I am relatively new to Core Data so please feel free to correct me if I am doing something else wrong...

Fstuff · July 2012

It's not Core Data that you appear to be having trouble with.

the _tempSet only adds one object and can not add anymore.

One of the hallsmarks of a set is that it contains distinct objects -- meaning that no two objects in the set are equal to each other. The only line of code that you posted where objects are added to your '_tempSet' adds a static string. So, no matter how many times you call [NSSet addObject], there will only be one occurrence of the string " " in your set. See the apple documentation for more details. https://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/Collections/Articles/Sets.html#//apple_ref/doc/uid/20000136-CJBDHAJD

and the second crashes when I click save right before the line [self.team addPlayers:_tempSet]; With the error [__NSCFConstantString _isKindOfEntity:]: unrecognized selector sent to instance 0xd7cd8'

I assume this is a roundabout way of saying the crash is happening on this line:

player.number  = cell.playerNumber.text;

Have you checked to ensure that the type of player.number is the same as the type of cell.playerNumber.text? Furthermore, what is cell? This looks a little suspect.

Howdy, Stranger!

Forums

NSMutableSet Core Data

Replies