我正在使用 NSPersistentCloudKitContainer 测试我的 CoreData + CloudKit Sync 的实现，它似乎在某些时候工作得很好。我解决了用户在 Apple 推荐的设置中打开/关闭 iCloud 的问题，但我现在遇到的问题是，当我离线测试我的应用程序时，当我通过互联网连接重新联机时，没有同步. 我有一些代码可以正确触发并检测是否存在互联网连接。但似乎仍然没有将容器选项设置为 nil 然后返回到 cloudkit 容器使其同步。到目前为止，这是我的代码：
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded 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.
*/
let container : NSPersistentContainer?
container = NSPersistentCloudKitContainer(name: "Model")
let description = NSPersistentStoreDescription(url: applicationDocumentsDirectory()!.appendingPathComponent("Model.sqlite"))
description.setOption(true as NSNumber,forKey: NSPersistentHistoryTrackingKey)
//Check if user is first logged onto iCloud enabled/not - if not then set cloudkitcontainer options to nil to disable sync and use the local DB on device
// This was from an accepted answer here: https://forums.developer.apple.com/thread/118924
//NB This works and the code here is triggered because a switch on/off icloud in settings kills the app and makes it restart, so this code is triggered.
if FileManager.default.ubiquityIdentityToken != nil { //logged onto iCloud*/
description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.my.container")
} else {
description.cloudKitContainerOptions = nil;
}
//However, turning a device to airplane mode on/off won't kill the app to trigger the above code, so have to put that check in with checking when the device is on or offline:
monitor.pathUpdateHandler = { path in
if path.status == .satisfied {
description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.my.container")
} else {
description.cloudKitContainerOptions = nil
}
}
//ensure migration------
description.shouldInferMappingModelAutomatically = true
description.shouldMigrateStoreAutomatically = true
//----------------------
container!.persistentStoreDescriptions = [description]
container!.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replace this implementation with code to handle the error appropriately.
// fatalError() 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.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
container!.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
container!.viewContext.automaticallyMergesChangesFromParent = true
return container!
}()
编辑
我只是从一个设备到另一个设备进行了尝试，如果一个设备在没有激活监视器实例的情况下暂时进入离线模式，它似乎可以工作（注释掉那部分代码以进行测试）。但是，如果设备长时间处于飞行模式，似乎不会发送 CloudKit 更新并且它是从其他设备同步的，而不是我正在使用的设备的最新更改......