Question

我试图用NSManagedObjectContext显示一个对象的值，但我不知道该怎么做这个代码。我应该使用NSManagedModel还是其他什么？

-(NSManagedObjectContext *) managedObjectContext {

    NSManagedObjectContext *context = nil;
    id delegate = [[UIApplication sharedApplication] delegate];

    if ([delegate performSelector:@selector(managedObjectContext)]) {

        context = [delegate managedObjectContext];
    }

    return context;
    }

- (void)viewDidLoad {
         [super viewDidLoad];

     NSManagedObjectContext *managedObjectContext = [self managedObjectContext];

     NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]initWithEntityName:@"Match"];

      self.playersArray = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy

     //What should I do here?

      UILabel *locationLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 100, 1000, 20)];
     [locationLabel setText: //trying to get this];
     [self.view addSubview:locationLabel];

}

我是xcode的初学者，对核心数据知之甚少。任何帮助表示赞赏。

我想做这样的事情：

 NSManagedObjectModel *playerModel = [self.playersArray objectAtIndex:indexPath.row]

然后执行：

[playerModel valueForKey: @"location"];

但我希望我的数据显示在视图控制器中而不是tableview控制器中。

Answer 1

假设您要显示数组中第一个玩家的位置并且该位置存储为字符串，您可以这样做：

....
 self.playersArray = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy

NSManagedObjectModel *playerModel = [self.playersArray objectAtIndex:0]

  UILabel *locationLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 100, 1000, 20)];
 [locationLabel setText:playerModel.location];
 [self.view addSubview:locationLabel];
....

如何使用NSManagedObjectContext

1 个答案: