Modèle de données de base Xcode 8 pour iOS 8,9

Question

Je développe une application dans un nouveau Xcode 8 et j'ai remarqué une chose évidente. Xcode m'a généré Core Data avec les dernières références d'API. Ainsi, si je modifie la cible de déploiement sur iOS 8 ou 9, cela crée un conflit et me propose de prendre entre crochets: AVAILABLE mon code Core Data. Cela signifie que je dois écrire à partir de zéro le code Core Data de la précédente API. Est-ce que quelqu'un a un modèle pour AppDelegate avec les deux ou est-il possible de faire en sorte que Xcode les génère? Merci d'avance!

Answer 1

Parce que personne ne devrait télécharger Xcode 7, l'installer, lancer un nouveau projet et transférer le code du modèle sur Swift 3 simplement pour utiliser les données de base tout en prenant en charge iOS 8 et 9:

Méthodes de modèle Swift 2 Core Data d'AppDelegate.Swift:

lazy var applicationDocumentsDirectory: NSURL = {
    // 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 = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .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 = NSBundle.mainBundle().URLForResource("coreDataTemplate", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: 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.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
    var failureReason = "There was an error creating or loading the application's saved data."
    do {
        try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
    } catch {
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason

        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()
        }
    }
}

Converti en Swift 3:

lazy 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]
}()

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: "coreDataTemplate", 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()
        }
    }
}

Answer 2

Merci à la réponse de DCToDaylight . J'ai fait ce fichier, que vous pouvez simplement glisser et déposer. J'ai également rendu mon contexte d'objet géré statique et ma méthode init privée. Pour que quelqu'un ne puisse pas instancier accidentellement un nouveau contexte.

La fonction appelée getContext facilite chaque fois que vous modifiez des données de base.

L'idée de créer un managedObjectContext statique, un fichier séparé et la fonction est venue de ce tutoriel YouTube .

Pour cet exemple, j'ai créé un nouveau fichier appelé DatabaseController.Swift et y ai mis tout ce code. Cela rendra simplement mon code plus facile à gérer et à lire. Vous pouvez également copier du // MARK: - Core Data stack au bas du fichier et remplacer le code similaire dans votre AppDelegate.Swift et cela fonctionnera.

import Foundation
import CoreData

class DatabaseController {

    private init() {

    }

    class func getContext () -> NSManagedObjectContext {
        return DatabaseController.managedObjectContext
    }
    // MARK: - Core Data stack

    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: "YOUR_APP_NAME", 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: "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
        }()

        // 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

    class 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()
            }
        }
    }
}

Cela dit, pour des raisons évidentes, vous ne pouvez pas utiliser NSPersistantContainer. Vous devez donc utiliser la méthode Core Data Stack à l'aide de managedObjectContext.

Answer 3

Si vous voulez une solution rapide à ce problème, il vous suffit d'ajouter une classe Objective C contenant une fonction générale de données centrale afin d'obtenir la référence de NSManagedObjectContext et de NSPersistentStoreCoordinator. (Vous pouvez trouver le code sur SO ou un autre site. Contactez-moi au cas où vous auriez besoin de cette classe.)

Après avoir ajouté la classe, utilisez la clause @Available 10 et, dans une autre partie, ajoutez du code pour prendre en référence le modèle susmentionné.

Faites-moi savoir si quelqu'un trouve quelque chose de mal avec elle.