Hey guys,
currently I'm working on a Swift3 / iOS10 update of an existing iOS9 App which stores about 10.000 charging points for electric vehicles across europe. Up to now I always shipped the Application with a pre-filled database (.sqlite, .sqlite-shm, .sqlite-wal files from the .xcappdata bundle), but with the current Version Apple is introducing the NSPersistentContainer Class, which makes it a bit more complicated. In my AppDelegate Class I'm instantiating my NSPersistentContainer object and passing it to a lazy var like it's done by Apple in every example code:
lazy var stationDataPersistentContainer: 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(name: "StationData")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
/*
* 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)")
}
})
return container
}()In the iOS9 version im copying the files to the apropriate directory, like you can see in the following code example:
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("StationData.sqlite")
let fileMgr = NSFileManager.defaultManager()
if !fileMgr.fileExistsAtPath(url.path!) {
do {
try fileMgr.copyItemAtPath(NSBundle.mainBundle().pathForResource("StationData", ofType: "sqlite")!, toPath: self.applicationDocumentsDirectory.URLByAppment("StationData.sqlite").path!)
try fileMgr.copyItemAtPath(NSBundle.mainBundle().pathForResource("StationData", ofType: "sqlite-shm")!, toPath: self.applicationDocumentsDirectory.URLByAppendingPathComponent("StationData.sqlite-shm").path!)
try fileMgr.copyItemAtPath(NSBundle.mainBundle().pathForResource("StationData", ofType: "sqlite-wal")!, toPath: self.applicationDocumentsDirectory.URLByAppendingPathComponent("StationData.sqlite-wal").path!)
} catch {
//
}
do {
try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url,
options: [NSMigratePersistentStoresAutomaticallyOption:true, NSInferMappingModelAutomaticallyOption:true])
} catch {
//
}
} else {
//
}
return coordinator
}()For a number of days I have tried to move the files to the proper directory which is returned by NSPersistentContainer.defaultDirectoryURL() -> URL, but everytime I get an error, that the file already exists because my stationDataPersistentContainer is already initialized and so the NSPersistentContainer had enough time to generate the sqlite* files. Even if I try to copy the files and initialize the stationDataPersistentContainer in an overwritten init() function I could not get this right. Is there anything I'm missing or overlooking in the documentation? Which is the best/right/appropriate way to copy existing data on installation of an App into coredata.
Appendix:
Just for your Information, I could also store the JSON-Files, which i get from my API into the Documents directory and run the JSON-parser, but this needs a lot of ressources and especially time!