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

Question

因此，当我尝试将部署目标设置为iOS 9时(确实低于10.0)，我得到了标题中所述的错误。

这里存在问题:

// 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
}()

查看不同的SO问题/答案，很明显，我需要添加一些代码来区分iOS 10是否可用。 Swift 3本身建议使用 @available(iOS 10.0, *)。但这还不够。我期望这是因为我错过了“如果不可用，请使用此功能”，但是对于Swift和iOS编程来说我是新手，所以我不确定该写些什么。而且我似乎找不到任何答案，无法给出关于所写内容的确切答案。有人可以帮忙吗？

Answer 1

您确实不需要将iOS 10与早期版本区分开。 NSPersistentContainer需要iOS 10，但是较旧的技术仍然有效并且仍受支持。如果您需要支持iOS <10，请不要使用NSPersistentContainer。加载托管对象模型和添加持久性存储要采取更多步骤，但这意味着您可以为所有版本的iOS使用单个代码路径。