ios - 保存的核心数据项仅在重新启动应用程序后可见

Question

1. RootVC.swift

   private let managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
   
   private var fetchRecordRequestController: NSFetchedResultsController = NSFetchedResultsController()
   override func viewDidLoad() {
       super.viewDidLoad()
       // Do any additional setup after loading the view, typically from a nib.
   
   // Initialize fetch request
   fetchRecordRequestController = NSFetchedResultsController(fetchRequest: fetchRecordRequest(), managedObjectContext: managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)
   fetchRecordRequestController.delegate = self
   // Fetch data from object
   do {
       try fetchRecordRequestController.performFetch()
   } catch let fetchError as NSError {
       print("(RootVC)fetchError: \(fetchError), \(fetchError.userInfo)")
   }}
   

2. AddRuleVC.swift

// 初始化 managedObjectContext 以从输入创建一个新对象

private var managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

// 将提取的值保存到 CoreData 对象的方法

func saveValues() {

// 设置，保存在私有队列中

let privateManagedObjectContext = NSManagedObjectContext(concurrencyType: .PrivateQueueConcurrencyType)
privateManagedObjectContext.persistentStoreCoordinator = managedObjectContext.persistentStoreCoordinator

// 初始化实体描述

let RuleDescription = NSEntityDescription.entityForName("Rule",inManagedObjectContext:privateManagedObjectContext)
let rule = Rule(entity: RuleDescription!, insertIntoManagedObjectContext: privateManagedObjectContext)

// 执行块

privateManagedObjectContext.performBlock { () -> Void in

// 从临时变量中设置对象值

rule.music = musicTemp! as MPMediaItemCollection
    print("musicTemp = \(musicTemp!.count)=========>saveValues")
// Save the object

    do {

    //print(NSStringFromClass((self.rule?.classForCoder)!))

            try rule.managedObjectContext?.save()
        } catch let saveError as NSError {
            print("(AddRuleViewController)saveError: \(saveError), \(saveError.userInfo)")
        }
    }
}

我的 RootVC 用于获取使用 AddRuleVC 存储的数据。我可以保存尽可能多的规则，但是一旦 AddRuleVC 回到 RootVC，它们就不会显示。它们仅在重新启动后出现。