【问题标题】:I am getting records from core data in ios 10 but I am not getting same records for iOS 9我正在从 ios 10 的核心数据中获取记录,但在 iOS 9 中没有得到相同的记录
【发布时间】:2017-08-23 06:11:05
【问题描述】:

在 iOS 10 中,我从核心数据中获取记录,但在 iOS 9 中没有获取相同的记录。

这是我的代码:

let request:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Airport")

let predicate  =  NSPredicate(format: "iata == %@", arrayData[i])
        request.predicate = predicate
do {
    airportData = try appDel?.databaseContext.fetch(request) as! [Airport]    
    print("data:\(airportData.count)")
} catch {
    print("Fetching Failed")
}

【问题讨论】:

  • 你有没有出错?
  • 您需要为 iOS 9 实现单独的代码行。这可能对您有帮助 stackoverflow.com/questions/44520394/…
  • 不,我没有收到任何错误。但是在为 ios9 和 ios 10 存储两个不同位置的 sqlite 文件时
  • 嗨。你检查过我的回答吗?您可以尝试一下并返回详细信息吗?

标签: ios swift core-data


【解决方案1】:

实际上这是重复的问题。对于 iOS 8 和 9,您应该实现另一个应用程序委托并使用 2 种不同的方式将数据插入数据库。

Xcode 8 Core Data Template for iOS 8,9

让我向您展示我项目中的示例。

类 AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    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 invalidate graphics rendering callbacks. 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 active 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.
    if #available(iOS 10.0, *) {
        self.saveContext()
    } else {
        self.saveOldStyleContext()
    }
}

// MARK: - Core Data stack
@available(iOS 10.0, *)
lazy var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "CafeManager")
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error as NSError? {
            //Error handling
            fatalError("Unresolved error \(error), \(error.userInfo)")
        }
    })
    return container
}()

@available(iOS 10.0, *)
static var persistantContainer: NSPersistentContainer {
    return (UIApplication.shared.delegate as! AppDelegate).persistentContainer
}

static var viewContext: NSManagedObjectContext {
    if #available(iOS 10.0, *) {
        return persistantContainer.viewContext
    } else {
        return AppDelegate.managedObjectContext
    }
}

// MARK: - Core Data stack for iOS 8+
static var managedObjectContext: NSManagedObjectContext = {

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

    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: "CafeManager", withExtension: "momd")!
        return NSManagedObjectModel(contentsOf: modelURL)!
    }()

    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: managedObjectModel)
        let url = 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: "iGlock.CafeManager.com", 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
    }()

    // 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 = persistentStoreCoordinator
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
}()

// MARK: - Core Data Saving support for iOS 10
@available(iOS 10.0, *)
func saveContext () {
    let context = persistentContainer.viewContext
    if context.hasChanges {
        do {
            try context.save()
        } catch {
            // Replace this implementation with code to handle the error appropriately.
            // fatalError() 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
            fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
        }
    }
}

// MARK: - Core Data Saving support for iOS 8+
func saveOldStyleContext () {
    if AppDelegate.managedObjectContext.hasChanges {
        do {
            try AppDelegate.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()
        }
    }
}
}

以及我如何处理 iOS 8-9 和 10+ 的插入请求:

class func addNewCustomGuest (guestName: String, tableSession: TableSessionTable) {
    if #available(iOS 10.0, *) {
        let newGuest = GuestsTable(context: context)
        newGuest.guestName = guestName
        newGuest.openTime = Date() as NSDate
        newGuest.closeTime = nil
        tableSession.addToGuest(newGuest)
    } else {
        let newGuest = GuestsTable(entity: NSEntityDescription.entity(forEntityName: "GuestsTable", in: context)!, insertInto: context)
        newGuest.guestName = guestName
        newGuest.openTime = Date() as NSDate
        newGuest.closeTime = nil
        tableSession.addToGuest(newGuest)
    }
    try? context.save()
}

同时获取请求适用于两个版本:

class func getActiveGuestsForTable (tableSession: TableSessionTable) -> [GuestsTable]? {
    guestTableRequest.predicate = NSPredicate(format: "table = %@ and closeTime = %@", tableSession, NSNull() as CVarArg)
    guestTableRequest.sortDescriptors = [NSSortDescriptor(key: "openTime", ascending: true, selector: #selector(NSDate.compare(_:)))]
    let matchedGuests = try? context.fetch(guestTableRequest)
    return matchedGuests
}

【讨论】:

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