Swift中适用于iOS 9和iOS 10的CoreData Stack
问题描述:
我正尝试将Core Data添加到支持iOS 9+的现有项目中。通过Xcode中产生Swift中适用于iOS 9和iOS 10的CoreData Stack
我已经添加代码:
// MARK: - Core Data stack
lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "tempProjectForCoreData")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext() {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
} catch {
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
在Xcode生成标准CoreData堆栈后,我发现了新的类NSPersistentContainer的是购自的iOS 10并且作为结果出现错误。
正确的CoreData Stack应该如何支持iOS 9和10?
答
这是为我工作的核心数据栈。我认为为了支持iOS 10我需要实现NSPersistentContainer
类,但是我发现使用NSPersistentStoreCoordinator
的旧版本也可以。
您必须更改您的模型(coreDataTemplate)和项目(SingleViewCoreData)的名称。
斯威夫特3:
// MARK: - CoreData Stack
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
managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
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()
}
}
}
答
使用接下来的结构适用于iOS 9和10
这是上下文中使用NEX并更换ModelCoreData为CoreData Storage.share的型号名称。背景
进口基金会 进口CoreData
/// NSPersistentStoreCoordinator延伸 扩展NSPersistentStoreCoordinator {
/// NSPersistentStoreCoordinator error types
public enum CoordinatorError: Error {
/// .momd file not found
case modelFileNotFound
/// NSManagedObjectModel creation fail
case modelCreationError
/// Gettings document directory fail
case storePathNotFound
}
/// Return NSPersistentStoreCoordinator object
static func coordinator(name: String) throws -> NSPersistentStoreCoordinator? {
guard let modelURL = Bundle.main.url(forResource: name, withExtension: "momd") else {
throw CoordinatorError.modelFileNotFound
}
guard let model = NSManagedObjectModel(contentsOf: modelURL) else {
throw CoordinatorError.modelCreationError
}
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: model)
guard let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last else {
throw CoordinatorError.storePathNotFound
}
do {
let url = documents.appendingPathComponent("\(name).sqlite")
let options = [ NSMigratePersistentStoresAutomaticallyOption : true,
NSInferMappingModelAutomaticallyOption : true ]
try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options)
} catch {
throw error
}
return coordinator
}
}
结构寄存{
static var shared = Storage()
@available(iOS 10.0, *)
private lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "ModelCoreData")
container.loadPersistentStores { (storeDescription, error) in
print("CoreData: Inited \(storeDescription)")
guard error == nil else {
print("CoreData: Unresolved error \(String(describing: error))")
return
}
}
return container
}()
private lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
do {
return try NSPersistentStoreCoordinator.coordinator(name: "ModelCoreData")
} catch {
print("CoreData: Unresolved error \(error)")
}
return nil
}()
private lazy var managedObjectContext: NSManagedObjectContext = {
let coordinator = self.persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: Public methods
enum SaveStatus {
case saved, rolledBack, hasNoChanges
}
var context: NSManagedObjectContext {
mutating get {
if #available(iOS 10.0, *) {
return persistentContainer.viewContext
} else {
return managedObjectContext
}
}
}
mutating func save() -> SaveStatus {
if context.hasChanges {
do {
try context.save()
return .saved
} catch {
context.rollback()
return .rolledBack
}
}
return .hasNoChanges
}
func deleteAllData(entity: String)
{
// let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = Storage.shared.context
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: entity)
fetchRequest.returnsObjectsAsFaults = false
do
{
let results = try managedContext.fetch(fetchRequest)
for managedObject in results
{
let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
managedContext.delete(managedObjectData)
}
} catch let error as NSError {
print("Detele all data in \(entity) error : \(error) \(error.userInfo)")
}
}
}
[检查这个](https://www.google.de/search?q = core + data + stack + ios9&ie = utf-8&oe = utf-8&client = firefox-b-ab&gfe_rd = cr&ei = upZSWN3dH7Go8wfJq5bQDQ) – shallowThought
为什么选择downvoted?感谢您的巨大努力和帮助@shallowThought ... 我在寻找并认为我需要将NSPersistentContainer以某种方式组合到堆栈中,这就是为什么要问。 – Bastek