Swift 3-“ NSPersistentContainer仅在ios 10和更高版本上可用”

Question

So I'm getting the error stated in the title when I try to set my deployment target to iOS 9 (really whatever below 10.0).

The problem exists here:

// MARK: - Core Data stack

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(name: "Keebin_development_1")
    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)")
    }
})
return container
}()

Looking at different SO questions/answers it's clear that I need to add some code to differentiate between whether iOS 10 is available or not. Swift 3 itself suggests using @available(iOS 10.0, *) . It's not enough though. I expect it's beacuse I'm missing a "if not available use this", however being new to Swift and iOS programming I am not sure what to write specifically. And I can't seem to find any answer giving the exact answer regarding what to write. Can someone help?

Answer 1

I was facing same issue and I resolved by the below mentioned way. I was doing project in Swift 3.0.

• I used pod 'INSPersistentContainer' and installed the pod in my project.
• Imported in APpDelegate by this line "import INSPersistentContainer"
• Then replace the NSPersistentContainer with INSPersistentContainer

And that's all.

Now I can run my App in lower version of iOS (< iOS 10).

Answer 2

You really don't need to distinguish iOS 10 from earlier versions. NSPersistentContainer requires iOS 10, but the older techniques still work and are still supported. If you need to support iOS <10, don't use NSPersistentContainer . It's more steps to load the managed object model and add the persistent store, but doing so means you can have a single code path for all versions of iOS.

Answer 3

NSPersistentContainer is only available from iOS 10

If you still need your app working in previous versions you can use the old Core Data Stack which is still work in iOS 10

The other solution would be use the #available attribute in swift to execute the Core Data Stack or the NSPersistentContainer.

You can follow https://stackoverflow.com/a/42392120/8023444 this answer to support both ios 9 and ios 10