无法保存到核心数据中

我有2个ViewControllers连接到Tab Bar Controller . 一个ViewController应显示来自核心数据的表数据，另一个具有两个输入文本字段并输入按钮以将输入数据保存到核心数据 . 但是，我无法使用'var managedObjectContext：NSManagedObjectContext？'进行保存 . 我没有使用任何segues传递数据 . 我的代码是否正确？

import UIKit
import CoreData

class AddNameViewController: UIViewController {

// MARK: - Properties

@IBOutlet var firstNameTextField: UITextField!
@IBOutlet var lastNameTextField: UITextField!

var person: Person?
var managedObjectContext: NSManagedObjectContext?


override func viewDidLoad() {
    super.viewDidLoad()

    title = "Add Name"

}

// MARK: - Actions

@IBAction func save(_ sender: UIButton) {
    guard let managedObjectContext = managedObjectContext else { return }

    if person == nil {
        let newName = Person(context: managedObjectContext)

        newName.firstName = firstNameTextField.text
        newName.lastName = lastNameTextField.text
        newName.createdAt = Date().timeIntervalSince1970

    }
    try? managedObjectContext.save()
}

}

我可能会误导所有人 . 这是我的表视图代码 . 我在AppDelegate中没有样板文件 .

import UIKit
import CoreData

class ViewController: UIViewController {

@IBOutlet var messageLabel: UILabel!
@IBOutlet var tableView: UITableView!
@IBOutlet var activityIndicatorView: UIActivityIndicatorView!

// MARK: - Persistent Container

private let persistentContainer = NSPersistentContainer(name: "People")

// MARK: - Fetch results controller

fileprivate lazy var fetchedResultsController:      NSFetchedResultsController<Person> = {
    let fetchRequest: NSFetchRequest<Person> = Person.fetchRequest()

    fetchRequest.sortDescriptors = [NSSortDescriptor(key: #keyPath(Person.createdAt), ascending: true
        )]

    let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.persistentContainer.viewContext, sectionNameKeyPath: #keyPath(Person.lastName), cacheName: nil)

    fetchedResultsController.delegate = self

    return fetchedResultsController
}()

override func viewDidLoad() {
    super.viewDidLoad()

    title = "People"

    persistentContainer.loadPersistentStores { (persistentSoreDescription, error) in
        if let error = error {
            print("Unable to load persistent store")
            print("\(error), \(error.localizedDescription)")
        } else {
            self.setupView()

            do {
                try self.fetchedResultsController.performFetch()
            } catch {
                let fetchError = error as NSError
                print("Unable to perform fetch request")
                print("\(fetchError), \(fetchError.localizedDescription)")
            }

            self.updateView()
        }
    }

    NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackground(_:)), name: Notification.Name.UIApplicationDidEnterBackground, object: nil)
}

// MARK: - Views

private func setupView() {
    setupMessageLabel()

    updateView()
}

fileprivate func updateView() {
    var hasNames = false

    if let people = fetchedResultsController.fetchedObjects {
        hasNames = people.count > 0
    }

    tableView.isHidden = !hasNames
    messageLabel.isHidden = hasNames

    activityIndicatorView.stopAnimating()
}

private func setupMessageLabel() {
    messageLabel.text = "You do not have names yet."
}

// MARK: - Notification handling

@objc func applicationDidEnterBackground(_ notification: Notification) {
    do {
        try persistentContainer.viewContext.save()
    } catch {
        print("Unable to save changes")
        print("\(error), \(error.localizedDescription)")
    }
}

}

extension ViewController: NSFetchedResultsControllerDelegate {

func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
    tableView.beginUpdates()
}

func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
    tableView.endUpdates()

    updateView()
}

    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
    switch (type) {
    case .insert:
        if let indexPath = newIndexPath {
            tableView.insertRows(at: [indexPath], with: .fade)
        }
        break
    case .delete:
        if let indexPath = indexPath {
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
        break
    case .update:
        if let indexPath = indexPath, let cell = tableView.cellForRow(at: indexPath) as? PersonTableViewCell {
            configure(cell, at: indexPath)
        }
    default:
        break

    }
}

    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange sectionInfo: NSFetchedResultsSectionInfo, atSectionIndex sectionIndex: Int, for type: NSFetchedResultsChangeType) {
    switch type {
    case .insert:
        tableView.insertSections(IndexSet(integer: sectionIndex), with: .fade)
    case .delete:
        tableView.deleteSections(IndexSet(integer: sectionIndex), with: .fade)
    default:
        break
    }
}

}

extension ViewController: UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
    guard let sections = fetchedResultsController.sections  else { return 0 }
    return sections.count
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    guard let sectionInfo = fetchedResultsController.sections?[section] else { fatalError("Unexpected section") }
    return sectionInfo.numberOfObjects
}

func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    guard let sectionInfo = fetchedResultsController.sections?[section] else { fatalError("Unexpected section") }
    return sectionInfo.name
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    guard let cell = tableView.dequeueReusableCell(withIdentifier: PersonTableViewCell.reuseIdentifier, for: indexPath) as? PersonTableViewCell else {
        fatalError("Unexpected indexPath")
    }

    // Configure cell
    configure(cell, at: indexPath)

    return cell
}

func configure(_ cell: PersonTableViewCell, at indexPath: IndexPath) {
    let name = fetchedResultsController.object(at: indexPath)

    // Configure cell
    cell.firstNameLabel.text = name.firstName
    cell.lastNameLabel.text = name.lastName
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        let name = fetchedResultsController.object(at: indexPath)

        name.managedObjectContext?.delete(name)
    }
}

}

extension ViewController: UITabBarDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    tableView.deselectRow(at: indexPath, animated: true)
}

}