在TableViewCells中查看Core Data的隐形问题
来自示例：https://drive.google.com/open?id=0B3d4jY23eLOoejdRWkE0SG1VMkk
步骤1.我实施了核心数据“数据库”。我现在有17条记录，想要通过TableView中的单元格查看所有这些记录... 
我做的就像在教程中一样，但它不起作用。我浪费了一个星期，并且找不到错误:(它加载完美，但数据不显示在单元格中:(所以...
import Foundation
import CoreData
@available(iOS 10.0, *)
class DatabaseController
{
private init() { }
class func getContext() -> NSManagedObjectContext
{
return persistentContainer.viewContext
}
// MARK: - Core Data stack
static var persistentContainer: NSPersistentContainer =
{
let container = NSPersistentContainer.init(name: "Database")
//let container = NSPersistentContainer(name: "Database")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError?
{
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
class func saveContext ()
{
let context = persistentContainer.viewContext
if context.hasChanges
{
do {
try context.save()
}
catch {
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
}
主要是3个文件...“DatabaseController.swift”中的save / get / persistant容器 接下来“AppDelegate.Swift”......
func applicationWillTerminate(_ application: UIApplication)
{
DatabaseController.saveContext()
}
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL =
{
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return urls[urls.count-1] as NSURL
}()
lazy var managedObjectModel: NSManagedObjectModel =
{
let modelURL = Bundle.main.url(forResource: "Database", withExtension: "momd")!
return NSManagedObjectModel(contentsOf: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? =
{
var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.appendingPathComponent("Database.sqlite")
var error: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
do
{
try coordinator!.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil)
}
catch {
coordinator = nil
let dict = NSMutableDictionary()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error
let error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict as? [AnyHashable : Any])
NSLog("Unresolved error \(String(describing: error)), \(error.userInfo)")
print(error.localizedDescription)
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext? =
{
let coordinator = self.persistentStoreCoordinator
if coordinator == nil
{
return nil
}
var managedObjectContext = NSManagedObjectContext()
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
负责DataCore的主要功能 和TableView的最终文件。在我将其作为DataCore之前，单元格显示为
if indexPath.row == 0 {
cell.postImageView.image = UIImage(named: "ENTP")
cell.postTitleLabel.text = "ENTP"
cell.authorLabel.text = "Oleksandr Zheliezniak"
cell.authorImageView.image = UIImage(named: "author"):
} else if indexPath.row == 1 {
cell.postImageView.image = UIImage(named: "INTJ")
cell.postTitleLabel.text = "INTJ"
cell.authorLabel.text = "Gabriel Theodoropoulos"
cell.authorImageView.image = UIImage(named: "appcoda-300")
} else if indexPath.row == 2 {
cell.postImageView.image = UIImage(named: "ENTP")
cell.postTitleLabel.text = "ENTJ"
cell.authorLabel.text = "Gabriel Theodoropoulos"
cell.authorImageView.image = UIImage(named: "appcoda-300")
} else {
cell.postImageView.image = UIImage(named: "СеКс")
cell.postTitleLabel.text = "и виски"
cell.authorLabel.text = "Кокс Карибский))"
cell.authorImageView.image = UIImage(named: "appcoda-300")
}
最终文件如下：
//
// PersonTableViewController.swift
//
// Created by Oleksandr Z 2017(c).
//
import UIKit
import Foundation
import CoreData
@available(iOS 10.0, *)
class PersonTableViewController: UITableViewController, NSFetchedResultsControllerDelegate
{
@IBAction func addButtonPressed(_ sender: Any)
{
switchScreen()
}
@IBOutlet weak var menuButton:UIBarButtonItem!
let moc: NSManagedObjectContext? = (UIApplication.shared.delegate as? AppDelegate)?.managedObjectContext
var fetchedResultsController: NSFetchedResultsController<NSFetchRequestResult>?
var valueToPass:String!
//override var prefersStatusBarHidden: Bool {return true}
override func viewDidLoad()
{
super.viewDidLoad()
// MARK: - CORE DATA fetching out to the TableView
fetchedResultsController?.delegate = self
fetchedResultsController = NSFetchedResultsController(fetchRequest: IdentitiesFetchRequest(), managedObjectContext: self.moc!, sectionNameKeyPath: nil, cacheName: nil)
do
{
try fetchedResultsController?.performFetch()
}
catch let error as NSError
{
fatalError("Failed to initialize FetchedResultsController: \(error)")
}
//Visualization
if self.revealViewController() != nil
{
self.revealViewController().rearViewRevealWidth = 250
self.revealViewController().frontViewShadowRadius = 10
self.revealViewController().frontViewShadowColor = UIColor.black
self.revealViewController().frontViewShadowOpacity = 1
menuButton.target = self.revealViewController()
menuButton.action = #selector(SWRevealViewController.revealToggle(_:))
self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
}
self.clearsSelectionOnViewWillAppear = true
}
func IdentitiesFetchRequest() -> NSFetchRequest<NSFetchRequestResult>
{
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Identity")
let sortDescriptor = NSSortDescriptor(key: "lastModified", ascending: true)
fetchRequest.predicate = nil
fetchRequest.sortDescriptors = [sortDescriptor]
fetchRequest.fetchBatchSize = 20
fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc!, sectionNameKeyPath: nil, cacheName: nil)
fetchedResultsController?.delegate = self
do
{
try fetchedResultsController?.performFetch()
}
catch
{
fatalError("Failed to initialize FetchedResultsController: \(error)")
}
return fetchRequest
}
//MARK: NSFetchedResultsController Delegate Functions
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete { }
switch editingStyle
{
case .delete:
do
{
moc?.delete(fetchedResultsController?.object(at: indexPath) as! Identity)
try moc?.save()
}
catch
{
print(error)
}
case .insert:
break
case .none:
break
}
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?)
{
switch type
{
case NSFetchedResultsChangeType.insert:
tableView.insertRows(at: NSArray(object: newIndexPath!) as! [IndexPath], with: UITableViewRowAnimation.fade)
break
case NSFetchedResultsChangeType.delete:
tableView.deleteRows(at: NSArray(object: indexPath!) as! [IndexPath], with: UITableViewRowAnimation.fade)
break
case NSFetchedResultsChangeType.move:
tableView.deleteRows(at: NSArray(object: indexPath!) as! [IndexPath], with: UITableViewRowAnimation.fade)
tableView.insertRows(at: NSArray(object: newIndexPath!) as! [IndexPath], with: UITableViewRowAnimation.fade)
break
case NSFetchedResultsChangeType.update:
tableView.cellForRow(at: indexPath! as IndexPath)
break
//default:
// break
}
}
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
{
tableView.beginUpdates()
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
{
tableView.endUpdates()
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
// Return the number of sections.
return fetchedResultsController?.sections?.count ?? 0
}
//Detailed viewCell
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
{
print("You selected cell #\(indexPath.row)!")
/*
// Get Cell Label
let indexPath = tableView.indexPathForSelectedRow!
let currentCell = tableView.cellForRow(at: indexPath)! as UITableViewCell
valueToPass = currentCell.textLabel?.text
performSegue(withIdentifier: "yourSegueIdentifer", sender: self)
*/
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
{
if (segue.identifier == "ShowPerson")
{
//var viewController = segue.destination as! PersonDetailViewController
//viewController.passedValue = valueToPass
}
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Return the number of rows in the section.
return fetchedResultsController?.sections?[section].numberOfObjects ?? 0
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as!PersonTableViewCell
if let cellContact = fetchedResultsController?.object(at: indexPath) as? Identity
{
cell.textLabel?.text = "\(String(describing: cellContact.pName)), \(String(describing: cellContact.lastModified))"
}
let identityClassName:String = String(describing: Identity.self)
//let typeClassName:String = String(describing: Type.self)
let identity:Identity = NSEntityDescription.insertNewObject(forEntityName: identityClassName, into: DatabaseController.getContext()) as! Identity
//let type:Type = NSEntityDescription.insertNewObject(forEntityName: typeClassName, into: DatabaseController.getContext()) as! Type
let fetchRequest:NSFetchRequest<Identity> = Identity.fetchRequest()
do
{
let searchResults = try DatabaseController.getContext().fetch(fetchRequest)
print("number of results: \(searchResults.count)")
for result in searchResults as [Identity]
{
print("\(result.pName!) is \(result.accuracy)% Robesper. Updeted \(result.lastModified!).")
cell.postImageView.image = UIImage(named: "ENTP")
cell.postTitleLabel.text = identity.pName
cell.authorLabel.text = identity.imType
cell.authorImageView.image = UIImage(named: "author")
}
}
catch { print("Error: \(error)") }
return cell
}
// Override to support rearranging the table view.
override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to toIndexPath: IndexPath) {
}
// Override to support conditional rearranging of the table view.
override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
// Return NO if you do not want the item to be re-orderable.
return true
}
func switchScreen()
{
let mainStoryboard = UIStoryboard(name: "Main", bundle: Bundle.main)
let vc : UIViewController = mainStoryboard.instantiateViewController(withIdentifier: "PersonDetail") as UIViewController
self.present(vc, animated: false, completion: nil)
}
}
尝试过的解决方案：Can't show the core data in tableview Swift但它没有帮助。尝试了所有类似的主题，但无法解决问题。
2 个答案:
答案 0 :(得分：0)
您似乎有两个单独的CoreData堆栈：一个由viewContext类设置，它使用NSPersistentContainer中的fetchedResultsController = NSFetchedResultsController(fetchRequest: IdentitiesFetchRequest(), managedObjectContext: self.moc!, sectionNameKeyPath: nil, cacheName: nil)
（在iOS10中引入），另一个设置在AppDelegate，它使用旧版项目模板中的标准样板文件。你的FRC使用后者，而你的其余代码使用前者。
虽然这些似乎使用相同的模型文件，但我怀疑他们正在使用不同的持久存储。我想如果你改变这一行：
fetchedResultsController = NSFetchedResultsController(fetchRequest: IdentitiesFetchRequest(), managedObjectContext: DatabaseController.getContext(), sectionNameKeyPath: nil, cacheName: nil)
为：
{{1}}
您的FRC将使用与创建对象的代码相同的上下文，因此您应该看到一些结果。您的代码还有其他问题，正如Tom Harrington在评论中所说，您应该学习如何使用调试器来解决这些问题。
答案 1 :(得分：0)
1) AES_ENCRYPT()
3) DES_ENCRYPT()
4) ENCRYPT()
5) COMPRESS()
我尝试了很多。无论使用哪种解决方案（扩展，懒惰，直接）。
你应该确定两个变量：一个用于所有数据数组;第二个是数组中的单个数据。
这就是它的基本工作方式：
var identities : [Identity] = []
override func viewDidLoad()
{
super.viewDidLoad()
tableView.dataSource = self
tableView.delegate = self
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