Core Data Framework With Multiple Targets - core-data

Question

I am currently making a project in swift 4 which uses a few targets. Since all the targets need to access the same core data, I have decided to make my own framework target which stores the data model for it as well as the access information for it.
The problem I am having is in my application target (CoreDataTest), when I run the application, I get the following error:
2017-09-17 12:02:20.787132+0100 CoreDataTest[22070:3218298] [error] error: Failed to load model named TestData
CoreData: error: Failed to load model named TestData
2017-09-17 12:02:20.787594+0100 CoreDataTest[22070:3218298] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'An NSManagedObject of class 'Message' must have a valid NSEntityDescription.'
*** First throw call stack:
(0x182097d38 0x1815ac528 0x18481a73c 0x1026c6678 0x1026c6708 0x1848bac5c 0x10261d480 0x10261ce94 0x10261cd48 0x10261cecc 0x18b42b96c 0x18b42b544 0x18b43210c 0x18b42f378 0x18b49edb4 0x18b68e570 0x18b693300 0x18b9129b4 0x18bbd90d0 0x18b912618 0x18b912e88 0x18c05daf4 0x18c05d998 0x18bde7ab4 0x18bf77c94 0x18bde7964 0x18bbd8730 0x18b691a44 0x18ba80144 0x18472d968 0x184736270 0x10344145c 0x10344db74 0x184761b04 0x1847617a8 0x184761d44 0x182040358 0x1820402d8 0x18203fb60 0x18203d738 0x181f5e2d8 0x183de3f84 0x18b48f5e0 0x10261deec 0x181a8256c)
libc++abi.dylib: terminating with uncaught exception of type NSException
I added an exception break point and it crashes in ViewController.swift at PersistenceStorage.saveContext().
How would I create a framework to create a shared Core Data database throughout my multiple targets in a single project?
Here is my project setup. Please note that each group is its own target.
Target: CoreDataKit (Framework)
CoreData.swift
import CoreData
public class PersistenceStorage {
private init() {}
public static var context: NSManagedObjectContext {
return persistentContainer.viewContext
}
public static var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "TestData")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
public static 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)")
}
}
}
}
Message+CoreDataClass.swift
import Foundation
import CoreData
#objc(Message)
public class Message: NSManagedObject {
}
Message+CoreDataProperties.swift
import Foundation
import CoreData
extension Message {
#nonobjc public class func fetchRequest() -> NSFetchRequest<Message> {
return NSFetchRequest<Message>(entityName: "Message")
}
#NSManaged public var text: String?
}
Target: CoreDataTest (Main Application)
ViewController.swift
import UIKit
import CoreDataKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let message = Message(context: PersistenceStorage.context)
message.text = "test"
PersistenceStorage.saveContext()
}
}
AppDelegate.swift
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
}

Answer 1

After a lot of research and trial and error, I found that I need to set the target members on the xcdatamodel file to the other targets that I wanted it to be shared with.

Answer 2

Just bumped into this myself so thought I'd post a couple other options.
Since you aren't subclassing NSPersistentContainer then it doesn't know where to look for bundles so has no option but to look in the main bundle.
If you want to only have your model in your framework then you could subclass NSPersistentContainer, or you can load the model first and pass that to the initialization of the persistent container. If you have only a single model then doing something like mergedModelFromBundles is pretty simple to do and then pass that model to the persistent container initializer.