multi-context-coredata

gistfile1.m

Solution 1:

NSMangedObjectContext *temporaryContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
temporaryContext.parentContext = mainMOC;
 
[temporaryContext performBlock:^{
   // do something that takes some time asynchronously using the temp context
 
   // push to parent
   NSError *error;
   if (![temporaryContext save:&error])
   {
      // handle error
   }
   
   // save parent to disk asynchronously
   [mainMOC performBlock:^{
      NSError *error;
      if (![mainMOC save:&error])
      {
         // handle error
      }
   }];
}];

Solution 2:

NSMangedObjectContext *temporaryContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
temporaryContext.persistentStoreCoordinator = mainMOC.persistentStoreCoordinator;
 
[temporaryContext performBlock:^{
   // do something that takes some time asynchronously using the temp context
 
   // push to parent
   NSError *error;
   if (![temporaryContext save:&error])
   {
      // handle error
   }
}];
}]; 

Child context

func didFinishViewController(
    viewController:JournalEntryViewController, didSave:Bool) {

    // 1
    if didSave {
      // 2
      var error: NSError? = nil
      let context = viewController.context
      context.performBlock({ () -> Void in
        if context.hasChanges && !context.save(&error) {
          println(
            "Couldn't save: \(error), \(error?.userInfo)")
          abort()
        }
        // 3
        self.coreDataStack.saveContext()
      })
    }
      
    // 4
    dismissViewControllerAnimated(true, completion: {})
  }