ios - 更新 CoreDataStack 时如何使用相同的数据库

Question

我正在更新我的 appDelegate 中的 CoreDataStack。但是，当我这样做时，我似乎丢失/没有使用与原始堆栈相同的数据库。数据库在持久存储上，更新堆栈时我没有更改 sqlite url。

self.storeDirectoryURL.URLByAppendingPathComponent("SingleViewCoreData.sqlite")

这是原始堆栈；

// MARK: - Core Data stack

lazy var applicationDocumentsDirectory: NSURL = {
    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("APPNAME", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: modelURL)!
}()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
    // 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
}()

新的 CoreDataStack

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    self.setupCoreData()

    try! managedObjectContext.save()

    // Setup Ensemble
    let modelURL = NSBundle.mainBundle().URLForResource("APPNAME", withExtension: "momd")
    cloudFileSystem = CDEICloudFileSystem(ubiquityContainerIdentifier: nil)

    ensemble = CDEPersistentStoreEnsemble(ensembleIdentifier: "APPNAME", persistentStoreURL: storeURL, managedObjectModelURL: modelURL!, cloudFileSystem: cloudFileSystem)
    ensemble.delegate = self


}

// MARK: - Core Data stack

var managedObjectContext: NSManagedObjectContext!

var storeDirectoryURL: NSURL {
    return try! NSFileManager.defaultManager().URLForDirectory(.ApplicationSupportDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true)
}

var storeURL: NSURL {
    return self.storeDirectoryURL.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
}

func setupCoreData() {
    let modelURL = NSBundle.mainBundle().URLForResource("APPNAME", withExtension: "momd")
    let model = NSManagedObjectModel(contentsOfURL: modelURL!)

    try! NSFileManager.defaultManager().createDirectoryAtURL(self.storeDirectoryURL, withIntermediateDirectories: true, attributes: nil)

    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: model!)
    let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]
    try! coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: self.storeURL, options: options)

    managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy

}

我哪里错了？我需要使用原始堆栈中的数据库。答案很可能是显而易见的，我对这一切都是陌生的。

Answer 1

问题在于初始化基本目录。

原文:

let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)

新:

return try! NSFileManager.defaultManager().URLForDirectory(.ApplicationSupportDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true) }

在原始堆栈中，您使用的是文档目录，而在新堆栈中，您使用的是支持目录。