ios - 核心数据包含空实体

Question

在我的核心数据 fetchRequest 中，一些返回的条目只包含 null，但是当我去保存我的数据时我没有看到任何错误。我试图弄清楚是什么导致了这个问题。

这是我第一次获取数据并保存的代码

- (IBAction)getCaredBtnPressed:(id)sender {
    NSString *urlString = [NSString stringWithFormat:@"http://netrunnerdb.com/api/cards/"];
    NSURL *url = [NSURL URLWithString:urlString];

    [NSURLConnection sendAsynchronousRequest:[[NSURLRequest alloc] initWithURL:url] queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        if (!connectionError){
            NSArray *dataArray = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];

            //Array that contains parsed JSON data
            for (NSDictionary *dict in dataArray){
                CorpCard *newEntry = [NSEntityDescription insertNewObjectForEntityForName:@"CorpCard" inManagedObjectContext:self.managedObjectContext];
                if ([[dict objectForKey:@"side"] isEqualToString:@"Corp"] && ![[dict objectForKey:@"setname"] isEqualToString:@"Special"]){
                    newEntry.type = [dict objectForKey:@"type"];
                    newEntry.title = [dict objectForKey:@"title"];
                    newEntry.text = [dict objectForKey:@"text"];
                    newEntry.subtype = [dict objectForKey:@"subtype"];
                    newEntry.faction = [dict objectForKey:@"faction"];
                    newEntry.influence = [dict objectForKey:@"factioncost"];
                    newEntry.unique = [dict objectForKey:@"uniqueness"];
                    newEntry.limit = [dict objectForKey:@"limited"];


                    //Add the entries to our database
                    if([[dict objectForKey:@"type"] isEqualToString:@"Identity"]){
                         newEntry.influence =[dict objectForKey:@"influencelimit"];
                        newEntry.minDeckSize =[dict objectForKey:@"minimumdecksize"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }


                    }
                    if([[dict objectForKey:@"type"] isEqualToString:@"Agenda"]) {
                        newEntry.cost = [dict objectForKey:@"advancementcost"];
                        newEntry.agendaPoint = [dict objectForKey:@"agendapoints"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }


                    }
                    if ([[dict objectForKey:@"type"] isEqualToString:@"Operation"]){
                        newEntry.cost = [dict objectForKey:@"cost"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }


                    }
                    if([[dict objectForKey:@"type"] isEqualToString:@"ICE"]){
                        newEntry.cost = [dict objectForKey:@"cost"];
                        newEntry.strength = [dict objectForKey:@"strength:"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }


                    }
                    if ([[dict objectForKey:@"type"] isEqualToString:@"Asset"]){
                        newEntry.cost = [dict objectForKey:@"cost"];
                        newEntry.trashCost = [dict objectForKey:@"trash"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }


                    }
                    if ([[dict objectForKey:@"type"] isEqualToString:@"Upgrade"]){
                        newEntry.cost = [dict objectForKey:@"cost"];
                        newEntry.trashCost = [dict objectForKey:@"trash"];
                        NSError *error;
                        if(![self.managedObjectContext save:&error]){
                            NSLog(@"Error occured, couldn't save: %@", [error localizedDescription]);
                        }
                    }
                    NSLog(@" added: %@, %@, %@, %@, %@, %@", [dict objectForKey:@"title"], [dict objectForKey:@"trash"], [dict objectForKey:@"cost"], [dict objectForKey:@"text"], [dict objectForKey:@"faction"], [dict objectForKey:@"type"]);

                }
            }   
        }            
    }];

}

这是我获取数据的代码

- (IBAction)prntCardsBtnPressed:(id)sender {
    //print out entries of our database
    AppDelegate *delegate = [UIApplication sharedApplication].delegate;
    self.corpCards = [delegate getAllCorpCards];
    int i;

    for (i =0; i <self.corpCards.count;i++){
         CorpCard *card = [self.corpCards objectAtIndex:i];
        NSLog(@"%@, %@, %@", card.title, card.text, card.type);
    }
}

最后，这里是执行在委托(delegate)中调用的获取的方法。

-(NSArray *)getAllFactionCards:(NSString *)faction{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:faction inManagedObjectContext:self.managedObjectContext];

    [fetchRequest setEntity:entity];
    NSError *error;

    NSArray *cards = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

    return cards;
}

最后，这是来自配音的片段。并非每个条目都返回 null

2014-09-01 18:06:33.780 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.782 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.783 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.783 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.784 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.784 NetrunnerApp[2205:60b] Melange Mining Corp., [Click], [Click], [Click]: Gain 7[Credits]., Asset
2014-09-01 18:06:33.785 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.785 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.786 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.786 NetrunnerApp[2205:60b] Scorched Earth, Play only if the runner is tagged.

Do 4 meat damage., Operation
2014-09-01 18:06:33.787 NetrunnerApp[2205:60b] Private Security Force, If the Runner is tagged, Private Security Force gains: "[Click]: Do 1 meat damage.", Agenda
2014-09-01 18:06:33.787 NetrunnerApp[2205:60b] Adonis Campaign, Put 12[Credits] from the bank on Adonis Campaign when rezzed. When there are no credits left on this card, trash it.

Take 3[Credits] from Adonis Campaign when your turn begins., Asset
2014-09-01 18:06:33.789 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.790 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.790 NetrunnerApp[2205:60b] Eli 1.0, The Runner may spend [Click] to break any subroutine on Eli 1.0.

[Subroutine] End the run.

[Subroutine] End the run., ICE
2014-09-01 18:06:33.791 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.791 NetrunnerApp[2205:60b] Haas-Bioroid: Engineering the Future, The first time you install a card each turn, gain 1[Credits]., Identity
2014-09-01 18:06:33.792 NetrunnerApp[2205:60b] NBN: Making News, 2[Recurring Credits]

Use these credits during trace attempts., Identity
2014-09-01 18:06:33.792 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.792 NetrunnerApp[2205:60b] (null), (null), (null)
2014-09-01 18:06:33.793 NetrunnerApp[2205:60b] Jinteki: Personal Evolution, Whenever an agenda is scored or stolen, do 1 net damage., Identity

Answer 1

你的问题在这里 -

  for (NSDictionary *dict in dataArray){
      CorpCard *newEntry = [NSEntityDescription insertNewObjectForEntityForName:@"CorpCard" inManagedObjectContext:self.managedObjectContext];
      if ([[dict objectForKey:@"side"] isEqualToString:@"Corp"] && ![[dict objectForKey:@"setname"] isEqualToString:@"Special"]){

您正在对象上下文中创建一个新条目，但随后检查字典中的值以查看是否应该填充它。即使您不填充它，新对象仍然位于您的托管对象上下文中，等待下一次调用 save。

您只需要重新构建循环的开始 -

for (NSDictionary *dict in dataArray) {
    if ([[dict objectForKey:@"side"] isEqualToString:@"Corp"] && ![[dict objectForKey:@"setname"] isEqualToString:@"Special"]) {
         CorpCard *newEntry = [NSEntityDescription insertNewObjectForEntityForName:@"CorpCard" inManagedObjectContext:self.managedObjectContext];

这样您只在需要时才创建新对象。