我刚刚为用户添加了在我的应用程序内切换云同步的选项，该选项将用户是否要在“ useCloudSync”下的UserDefaults中使用iCloud同步保存。当应用运行时，我加载我的persistentContainer：
class CoreDataManager {
static let sharedManager = CoreDataManager()
private init() {}
lazy var persistentContainer: NSPersistentContainer = {
var useCloudSync = UserDefaults.standard.bool(forKey: "useCloudSync")
let containerToUse: NSPersistentContainer?
if useCloudSync {
containerToUse = NSPersistentCloudKitContainer(name: "App")
} else {
containerToUse = NSPersistentContainer(name: "App")
let description = containerToUse!.persistentStoreDescriptions.first
description?.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
}
guard let container = containerToUse, let description = container.persistentStoreDescriptions.first else {
fatalError("Hey Listen! ###\(#function): Failed to retrieve a persistent store description.")
}
description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
...
return container
}
}
当用户使用UISwitcher切换云同步时，我在UserDefaults中更改了“ useCloudSyc”的值，但是该应用程序不使用，NSPersistentCloudKitContainer除非他们强制关闭该应用程序并再次运行。我希望当用户切换开关以开始从iCloud加载数据时，容器会正确更改。
NSPersistentCloudKitContainer当用户切换“ CloudSync”时，如何更改与？
这是可能的方法
extension UserDefaults { // helper key path for observing
@objc dynamic var useCloudSync: Bool {
return bool(forKey: "useCloudSync")
}
}
class CoreDataManager {
static let sharedManager = CoreDataManager()
private var observer: NSKeyValueObservation?
private init() {
}
lazy var persistentContainer: NSPersistentContainer = {
setupContainer()
}()
private func setupContainer() -> NSPersistentContainer {
if nil == observer {
// setup observe for defults changed
observer = UserDefaults.standard.observe(\.useCloudSync) { [weak self] (_, _) in
try? self?.persistentContainer.viewContext.save() // save anything pending
if let newContainer = self?.setupContainer() {
self?.persistentContainer = newContainer
}
}
}
let useCloudSync = UserDefaults.standard.bool(forKey: "useCloudSync")
let containerToUse: NSPersistentContainer?
if useCloudSync {
containerToUse = NSPersistentCloudKitContainer(name: "App")
} else {
containerToUse = NSPersistentContainer(name: "App")
let description = containerToUse!.persistentStoreDescriptions.first
description?.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
}
guard let container = containerToUse, let description = container.persistentStoreDescriptions.first else {
fatalError("Hey Listen! ###\(#function): Failed to retrieve a persistent store description.")
}
description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
container.loadPersistentStores { (storeDescription, error) in
// ...
}
return container
}
}
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