关于 ios:Swift 3 Core Data 问题 – All Data Missing

Swift 3 Core Data issue - All Data Missing

我将我的 Core Data 项目从 Swift 2 升级到 Swift 3。用 NSPersistentContainer 替换 Core Data 堆栈。但是新版本找不到旧数据。

Swift

安装新版本后：

Swift

Swift 3 版本应用找不到任何数据

我的应用程序的功能是记录单词/句子及其中文含义。如果我在App Store上发布此版本，用户将在更新后丢失所有记录。

我该如何解决这个问题？

这是我的 Swift 3 代码：

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// 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"social.street.NewWords" in the application's documents Application Support directory.
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return urls[urls.count-1]
}()

lazy var persistentContainer: NSPersistentContainer = {
let modelURL = Bundle.main.url(forResource:"NewWords", withExtension:"momd")!
let container = NSPersistentContainer(name:"NewWords", managedObjectModel: NSManagedObjectModel(contentsOf: modelURL)!)

let documentsDirectory = FileManager.default.urls(for: FileManager.SearchPathDirectory.documentDirectory, in: FileManager.SearchPathDomainMask.userDomainMask)

let storeUrl = self.applicationDocumentsDirectory.appendingPathComponent("SingleViewCoreData.sqlite")

print(storeUrl)

container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: storeUrl)]

container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as? NSError {
fatalError("Unresolved error \\(error), \\(error.userInfo)")
}
})
return container
}()

Swift 2 代码：

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// 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"social.street.NewWords" 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("NewWords", 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
}()

代码升级到 Swift 3 后如何保留数据？

另外：swift 2版本是从App Store安装的，swift 3版本是从Xcode安装的。

项目的 Github 存储库