Question

我已经使用CoreData填充了一个数据库，现在我想在swift中将它用作我的应用程序中的默认数据库。我已经读过它，但我只在Objective-C中找到了教程，Xcode6在AppDelegate中创建的Core Data方法对我来说很奇怪......

这是代码：

    // MARK: - Core Data stack

lazy var applicationDocumentsDirectory: NSURL = {
    // The directory the application uses to store the Core Data store file. This code uses a directory named "RLopez.BORRAME" in the application's documents Application Support directory.
    let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
    return urls[urls.count-1] as NSURL
    }()

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("iManager", withExtension: "momd")
    return NSManagedObjectModel(contentsOfURL: modelURL)
    }()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    // The persistent store coordinator for the application. This implementation creates and return 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
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("iManager.sqlite")
    println(url)
    var error: NSError? = nil
    var failureReason = "There was an error creating or loading the application's saved data."
    if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
        coordinator = nil
        // Report any error we got.
        let dict = NSMutableDictionary()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError.errorWithDomain("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 \(error), \(error!.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
    if coordinator == nil {
        return nil
    }
    var managedObjectContext = NSManagedObjectContext()
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
    }()

// MARK: - Core Data Saving support

func saveContext () {
    if let moc = self.managedObjectContext {
        var error: NSError? = nil
        if moc.hasChanges && !moc.save(&error) {
            // 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.
            NSLog("Unresolved error \(error), \(error!.userInfo)")
            abort()
        }
    }
}

我想要的是使用我的应用程序包中的sqlite文件而不是创建一个空数据库。我怎样才能做到这一点？

提前致谢！

Answer 1

这是SWIFT2的正确方法：

 lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
        var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
        let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("db.sqlite")

        //this part
        if (!NSFileManager.defaultManager().fileExistsAtPath(url.path!)) {
            let defaultStorePath = NSBundle.mainBundle().pathForResource("db", ofType:"sqlite")

            do {
                try NSFileManager.defaultManager().copyItemAtPath(defaultStorePath!, toPath:url.path!)
            } catch _ {
            }
        }

        do {
            try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
        } catch _ {
            coordinator = nil
        }
        return coordinator
        }()

Answer 2

将sqlite文件从app bundle复制到持久存储所在的位置。

这是我的代码：

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("db.sqlite")

   //this part
    if (!NSFileManager.defaultManager().fileExistsAtPath(url.path!)) {
        let defaultStorePath = NSBundle.mainBundle().pathForResource("db", ofType:"sqlite")

        NSFileManager.defaultManager().copyItemAtPath(defaultStorePath!, toPath:url.path!, error: nil)
    }

    if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: nil) == nil {
        coordinator = nil
    }
    return coordinator
    }()

Answer 3

斯威夫特3：

    lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = Globals.userDocumentsURL.appendingPathComponent("db.sqlite")


    //this part
    if (!FileManager.default.fileExists(atPath: url.path)) {
        let defaultStorePath = Bundle.main.path(forResource: "db", ofType:"sqlite")

        do {
            try FileManager.default.copyItem(atPath: defaultStorePath!, toPath:url.path)
        } catch _ {
        }
    }

    do {
        try coordinator!.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil)
    } catch _ {
        coordinator = nil
    }
    return coordinator
}()

swift - 来自预先填充的SQLite的核心数据

3 个答案: