我觉得我失去了我的托管对象上下文

Question

所以我的工作CoreDataBooks的克隆。 有点不同。当按下“+”按钮时，它将启动一个包含2个视图的navController。第一个（AddPatientVC）询问病人的姓名，然后将其推送到第二个视图控制器（AddPatientDetailVC），该控制器询问更详细的信息。这是第二个视图控制器，我已经设置了代理，而不是像CoreDataBooks中的第一个。

出于某种原因，当委托方法被触发，该通知方法不被解雇，所以我莫名其妙地失去了跟踪我的MOC的，无论是具体的MOC添加一个新的病人。

特定的错误我得到的是：“+ entityForName：未能找到NSManagedObjectModel为实体名称'病人”

这里是我的代码 - addPatient，委托方法和通知方法。任何关于简化的建议将不胜感激。感谢名单

---

-(void)addPatient:(id)sender 
{ 
    PatientAddViewController *patientAddViewController = [[PatientAddViewController alloc] initWithNibName:@"PatientAddViewController" bundle:nil]; 

    PatientAddDetailViewController *patientAddDetailViewController = [[PatientAddDetailViewController alloc] initWithNibName:@"PatientAddViewController" bundle:nil]; 
    patientAddDetailViewController.delegate = self; 

    //Create a new MOC for adding a book 
    NSManagedObjectContext *addingContext = [[NSManagedObjectContext alloc] init]; 
    self.addPatientManagedObjectContext = addingContext; 
    [addingContext release]; 


    [addPatientManagedObjectContext setPersistentStoreCoordinator:[[fetchedResultsController managedObjectContext] persistentStoreCoordinator]]; 
    patientAddViewController.patient = (Patient *)[NSEntityDescription insertNewObjectForEntityForName:@"Patient" inManagedObjectContext:addingContext]; 



    //patientAddViewController.addPatientManagedObjectContext = self.addPatientManagedObjectContext; 
    UINavigationController *addingNavController = [[UINavigationController alloc] initWithRootViewController:patientAddViewController]; 
    [self.navigationController presentModalViewController:addingNavController animated:YES]; 

    [addingNavController release]; 
    [patientAddViewController release]; 

    } 


- (void)patientAddDetailViewController:(PatientAddDetailViewController *)controller didFinishWithSave:(BOOL)save 
{ 
    NSLog(@"Delegate Method fired"); 
    if (save) 
    {  
     NSNotificationCenter *dnc = [NSNotificationCenter defaultCenter]; 

     //The notification isn't firing becuase addPatientManagedObjectContext is null for some reason 
     [dnc addObserver:self selector:@selector(addControllerContextDidSave:) name:NSManagedObjectContextDidSaveNotification object:addPatientManagedObjectContext]; 

     NSError *error; 
     //if (![patient.managedObjectContext save:&error]) 
     if (![addPatientManagedObjectContext save:&error]) 
     { 
      NSLog(@"Before Error"); 
      //Handle the error... 
      NSLog(@"Unresolved Error %@, %@",error, [error userInfo]); 
      exit(-1);//Fail 
      NSLog(@"After Error"); 
     } 


     [dnc removeObserver:self name:NSManagedObjectContextDidSaveNotification object:addPatientManagedObjectContext]; 
    } 
    self.addPatientManagedObjectContext = nil; 
    [self.tableView reloadData]; 

    [self dismissModalViewControllerAnimated:YES]; 

} 

- (void)addControllerContextDidSave:(NSNotification*)saveNotification { 

    NSLog(@"Save Notification Fired"); 

    NSManagedObjectContext *context = [fetchedResultsController managedObjectContext]; 

    // Merging changes causes the fetched results controller to update its results 
    [context mergeChangesFromContextDidSaveNotification:saveNotification]; 
} 

Answer 1

看起来你创建上下文，并将其存储在self

NSManagedObjectContext *addingContext = [[NSManagedObjectContext alloc] init]; 
self.addPatientManagedObjectContext = addingContext; 
[addingContext release]; 

但随后调用其他控制器上的 “添加” 方法：

patientAddViewController.patient = (Patient *)[NSEntityDescription 
    insertNewObjectForEntityForName:@"Patient" inManagedObjectContext:addingContext]; 

（记住，你发布的“addingContext”了上面，“addingContext”不能保证包含任何有效的在这个POI nt）

看起来您应该在您的insertNewObjectForEntityForName:@"Patient"行中传递self.addPatientManagedObjectContext而不是addingContext。