Ios 核心数据关系不持久

我试图向集合中添加一个实体，但它在应用程序关闭后不会持久化。我的关系是这样的：

 guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }

    // 1
    let managedContext =
        appDelegate.persistentContainer.viewContext

    // 2
    let entity =
        NSEntityDescription.entity(forEntityName: "Task",
                                   in: managedContext)!


    let task = NSManagedObject(entity: entity,
                                insertInto: managedContext)

    // 3
    task.setValue(cell.taskTextField.text, forKeyPath: "name")

    // 4
    do {
        try managedContext.save()
    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }

 groups[0].mutableSetValue(forKey: "tasks").add(task)

我创建了一个新任务，如下所示：

 guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }

    // 1
    let managedContext =
        appDelegate.persistentContainer.viewContext

    // 2
    let entity =
        NSEntityDescription.entity(forEntityName: "Task",
                                   in: managedContext)!


    let task = NSManagedObject(entity: entity,
                                insertInto: managedContext)

    // 3
    task.setValue(cell.taskTextField.text, forKeyPath: "name")

    // 4
    do {
        try managedContext.save()
    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }

 groups[0].mutableSetValue(forKey: "tasks").add(task)

我将任务添加到组实体，如下所示：

 guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }

    // 1
    let managedContext =
        appDelegate.persistentContainer.viewContext

    // 2
    let entity =
        NSEntityDescription.entity(forEntityName: "Task",
                                   in: managedContext)!


    let task = NSManagedObject(entity: entity,
                                insertInto: managedContext)

    // 3
    task.setValue(cell.taskTextField.text, forKeyPath: "name")

    // 4
    do {
        try managedContext.save()
    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }

 groups[0].mutableSetValue(forKey: "tasks").add(task)

其中groups是一个NSManagedObject数组，其值加载在

viewDidLoad:

中，如下所示：

   //1
    guard let appDelegate =
        UIApplication.shared.delegate as? AppDelegate else {
            return
    }

    let managedContext =
        appDelegate.persistentContainer.viewContext

    //2
    let fetchRequest =
        NSFetchRequest<NSManagedObject>(entityName: "Group")


    //3
    do {
        groups = try managedContext.fetch(fetchRequest)
    } catch let error as NSError {
        print("Could not fetch. \(error), \(error.userInfo)")
    }

---

如果我不打开和关闭应用程序，此代码将打印任务。由于某些原因，应用程序关闭时数据不会持久化。有什么想法吗？谢谢

请确保将上下文一直保存到持久存储（而不仅仅是父上下文）

将任务添加到组后是否保存上下文？我在上面的例子中没有看到。必须这样做。不相关，但不要保护

AppDelegate

。强行打开它。如果类丢失，你的应用程序甚至不会启动。