Question

我有一个关于Swift 3与Core Data相关的问题。我正在使用Xcode 8在Swift中开发一个App，我需要支持iOS 9和iOS10。问题是我不知道如何获取AppDelegate和Context（用于存储和从我的实体获取数据）。我认为我的代码应该是这样的：

#if avaliable(iOS10,*)
{
     // iOS 10 code
} else
{
    // iOS 9 code
}

但我不知道该怎么做。

有什么想法吗？

（赞赏修正的小帮助）

Answer 1

#Swift 3中的代码适用于iOS 9和iOS 10的核心数据＃

由于您需要iOS 9和iOS 10的核心数据代码，因此您不必使用{9}在iOS 9中不支持，因此您必须使用旧方法

如果在项目创建时您没有包含核心数据，之后您想要包含核心数据，请按照以下步骤操作： -

第1步。转到NSPersistentContainer - ＆gt; Build Phases - ＆gt; Link Binary with Library - ＆gt; click on + sign

第2步。现在到了Add CoreData.framework。

第3步。现在您需要在file -> New File -> select Data Model中编写一些代码来设置go： -

AppDelegate.swift

这就是您在Swift 3中为iOS 9和iOS 10准备好的所有核心数据。享受!!!

Answer 2

如果你想支持iOS9，那么最好不要使用任何新的iOS10东西。

现在坚持使用iOS9 API，将来当您最终放弃iOS9支持时，您可以重构代码以使用更新的方法。

编辑：为了清楚起见，所有iOS9代码都可以在iOS10上正常运行。你不需要做任何特殊的事情，它都是向后兼容的。

Answer 3

同时支持iOS9和iOS10的CoreData

对于你可能需要的人：

这是来自2016年5月最新Xcode7（iOS9）版本的未经修改的Master-Detail App模板。我已使用当前最新的Xcode（版本8.2.1）更新了它

使用此模板，您可以开发一个使用与iOS9和iOS10兼容的CoreData的应用程序，至少目前（2017年5月）

<强> AppDelegate.swift

//
//  AppDelegate.swift
//  trash
//
//  Created by Markus on 22/05/17.
//  Copyright © 2017 Markus. All rights reserved.
//

import UIKit
import CoreData

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDelegate {

var window: UIWindow?


func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    let splitViewController = self.window!.rootViewController as! UISplitViewController
    let navigationController = splitViewController.viewControllers[splitViewController.viewControllers.count-1] as! UINavigationController
    navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem
    splitViewController.delegate = self

    let masterNavigationController = splitViewController.viewControllers[0] as! UINavigationController
    let controller = masterNavigationController.topViewController as! MasterViewController
    controller.managedObjectContext = self.managedObjectContext
    return true
}

func applicationWillResignActive(_ application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

func applicationDidEnterBackground(_ application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

func applicationWillEnterForeground(_ application: UIApplication) {
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

func applicationDidBecomeActive(_ application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

func applicationWillTerminate(_ application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    // Saves changes in the application's managed object context before the application terminates.
    self.saveContext()
}

// MARK: - Split view

func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController:UIViewController, onto primaryViewController:UIViewController) -> Bool {
    guard let secondaryAsNavController = secondaryViewController as? UINavigationController else { return false }
    guard let topAsDetailController = secondaryAsNavController.topViewController as? DetailViewController else { return false }
    if topAsDetailController.detailItem == nil {
        // Return true to indicate that we have handled the collapse by doing nothing; the secondary controller will be discarded.
        return true
    }
    return false
}
// MARK: - Core Data stack

lazy var applicationDocumentsDirectory: URL = {
    // The directory the application uses to store the Core Data store file. This code uses a directory named "com.senbei.trash" in the application's documents Application Support directory.
    let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
    return urls[urls.count-1]
}()

lazy var managedObjectModel: NSManagedObjectModel = {
    // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
    let modelURL = Bundle.main.url(forResource: "trash", withExtension: "momd")!
    return NSManagedObjectModel(contentsOf: modelURL)!
}()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
    // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
    // Create the coordinator and store
    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.appendingPathComponent("SingleViewCoreData.sqlite")
    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 {
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject?
        dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject?

        dict[NSUnderlyingErrorKey] = error as NSError
        let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        // Replace this with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
        abort()
    }

    return coordinator
}()

lazy var managedObjectContext: NSManagedObjectContext = {
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
    let coordinator = self.persistentStoreCoordinator
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
}()

// MARK: - Core Data Saving support

func saveContext () {
    if managedObjectContext.hasChanges {
        do {
            try managedObjectContext.save()
        } catch {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            let nserror = error as NSError
            NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
            abort()
        }
    }
}

}

<强> MasterViewController.swift

//
//  MasterViewController.swift
//  trash
//
//  Created by Markus on 22/05/17.
//  Copyright © 2017 Markus. All rights reserved.
//


import UIKit
import CoreData

class MasterViewController: UITableViewController, NSFetchedResultsControllerDelegate {

var detailViewController: DetailViewController? = nil
var managedObjectContext: NSManagedObjectContext? = nil


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.navigationItem.leftBarButtonItem = self.editButtonItem

    let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(insertNewObject(_:)))
    self.navigationItem.rightBarButtonItem = addButton
    if let split = self.splitViewController {
        let controllers = split.viewControllers
        self.detailViewController = (controllers[controllers.count-1] as! UINavigationController).topViewController as? DetailViewController
    }
}

override func viewWillAppear(_ animated: Bool) {
    self.clearsSelectionOnViewWillAppear = self.splitViewController!.isCollapsed
    super.viewWillAppear(animated)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func insertNewObject(_ sender: AnyObject) {
    let context = self.fetchedResultsController.managedObjectContext
    let entity = self.fetchedResultsController.fetchRequest.entity!
    let newManagedObject = NSEntityDescription.insertNewObject(forEntityName: entity.name!, into: context)

    // If appropriate, configure the new managed object.
    // Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.
    newManagedObject.setValue(Date(), forKey: "timeStamp")

    // Save the context.
    do {
        try context.save()
    } catch {
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        //print("Unresolved error \(error), \(error.userInfo)")
        abort()
    }
}

// MARK: - Segues

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "showDetail" {
        if let indexPath = self.tableView.indexPathForSelectedRow {
        let object = self.fetchedResultsController.object(at: indexPath)
            let controller = (segue.destination as! UINavigationController).topViewController as! DetailViewController
            controller.detailItem = object
            controller.navigationItem.leftBarButtonItem = self.splitViewController?.displayModeButtonItem
            controller.navigationItem.leftItemsSupplementBackButton = true
        }
    }
}

// MARK: - Table View

override func numberOfSections(in tableView: UITableView) -> Int {
    return self.fetchedResultsController.sections?.count ?? 0
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let sectionInfo = self.fetchedResultsController.sections![section]
    return sectionInfo.numberOfObjects
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
    let object = self.fetchedResultsController.object(at: indexPath) as! NSManagedObject
    self.configureCell(cell, withObject: object)
    return cell
}

override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    // Return false if you do not want the specified item to be editable.
    return true
}

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        let context = self.fetchedResultsController.managedObjectContext
        context.delete(self.fetchedResultsController.object(at: indexPath) as! NSManagedObject)

        do {
            try context.save()
        } catch {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            //print("Unresolved error \(error), \(error.userInfo)")
            abort()
        }
    }
}

func configureCell(_ cell: UITableViewCell, withObject object: NSManagedObject) {
    //cell.textLabel!.text = object.value(forKey: "timeStamp")!.description
    cell.textLabel!.text = (object.value(forKey: "timeStamp")! as AnyObject).description
}

// MARK: - Fetched results controller

//var fetchedResultsController: NSFetchedResultsController {

var fetchedResultsController: NSFetchedResultsController<NSFetchRequestResult> {
    if _fetchedResultsController != nil {
        return _fetchedResultsController!
    }

    //let fetchRequest = NSFetchRequest()

    //let fetchRequest = NSFetchRequest<Event>(entityName: "Event") //another alternative

    let fetchRequest:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Event")


    // Edit the entity name as appropriate.
    let entity = NSEntityDescription.entity(forEntityName: "Event", in: self.managedObjectContext!)
    fetchRequest.entity = entity

    // Set the batch size to a suitable number.
    fetchRequest.fetchBatchSize = 20

    // Edit the sort key as appropriate.
    let sortDescriptor = NSSortDescriptor(key: "timeStamp", ascending: false)

    fetchRequest.sortDescriptors = [sortDescriptor]

    // Edit the section name key path and cache name if appropriate.
    // nil for section name key path means "no sections".
    let aFetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.managedObjectContext!, sectionNameKeyPath: nil, cacheName: "Master")
    aFetchedResultsController.delegate = self
    _fetchedResultsController = aFetchedResultsController

    do {
        try _fetchedResultsController!.performFetch()
    } catch {
         // Replace this implementation with code to handle the error appropriately.
         // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
         //print("Unresolved error \(error), \(error.userInfo)")
         abort()
    }

    return _fetchedResultsController!
}
//var _fetchedResultsController: NSFetchedResultsController? = nil

var _fetchedResultsController: NSFetchedResultsController<NSFetchRequestResult>?

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

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

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
    switch type {
        case .insert:
            tableView.insertRows(at: [newIndexPath!], with: .fade)
        case .delete:
            tableView.deleteRows(at: [indexPath!], with: .fade)
        case .update:
            self.configureCell(tableView.cellForRow(at: indexPath!)!, withObject: anObject as! NSManagedObject)
        case .move:
            tableView.moveRow(at: indexPath!, to: newIndexPath!)
    }
}

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

/*
 // Implementing the above methods to update the table view in response to individual changes may have performance implications if a large number of changes are made simultaneously. If this proves to be an issue, you can instead just implement controllerDidChangeContent: which notifies the delegate that all section and object changes have been processed.

 func controllerDidChangeContent(controller: NSFetchedResultsController) {
     // In the simplest, most efficient, case, reload the table view.
     self.tableView.reloadData()
 }
 */

}

<强> DetailViewController.swift

//
//  DetailViewController.swift
//  trash
//
//  Created by Markus on 22/05/17.
//  Copyright © 2017 Markus. All rights reserved.
//

import UIKit

class DetailViewController: UIViewController {

@IBOutlet weak var detailDescriptionLabel: UILabel!


var detailItem: AnyObject? {
    didSet {
        // Update the view.
        self.configureView()
    }
}

func configureView() {
    // Update the user interface for the detail item.
    if let detail = self.detailItem {
        if let label = self.detailDescriptionLabel {
            //label.text = detail.value(forKey: "timeStamp")!.description
            label.text = (detail.value(forKey: "timeStamp")! as AnyObject).description
        }
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.configureView()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

数据模型是模板中的原始模型，也是故事板。两者都没有修改。

Answer 4

您可以使用新API并通过执行以下操作获得好处：

var coreDataManager: CoreDataManagerProtocol!
#if available(iOS10,*)
{
    coreDataManager = CoreDataManagerNewStack()
} else
{
    coreDataManager = CoreDataManagerOldStack()
}

然后使用新堆栈将新CoreData实现到类中：

class CoreDataManagerNewStack: CoreDataManagerProtocol {
    var container: NSPersistentContainer
    // etc
}

以及上面带有代码paster的旧代码，用整个代码生成堆栈

class CoreDataManagerOldStack: CoreDataManagerProtocol {
     lazy var managedObjectContext: NSManagedObjectContext = {
        // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
        let coordinator = self.persistentStoreCoordinator
        var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
        managedObjectContext.persistentStoreCoordinator = coordinator
        return managedObjectContext
    }()
    // etc
}

iOS 9和iOS 10 CoreData同时出现

4 个答案: