swift - 无法将类型 '__NSCFSet' (0x109b56408) 的值转换为 'NSArray' Swift 4

Question

我正在尝试从 notification.userInfo 中获取一组位置对象，插入和删除值并相应地更新 map 注释。它不允许我将其转换为 [Location] 类型。

出现以下错误

Could not cast value of type '__NSCFSet' (0x109b56408) to 'NSArray'

var managedObjectContext: NSManagedObjectContext! {
    didSet {
        NotificationCenter.default.addObserver(forName: Notification.Name.NSManagedObjectContextObjectsDidChange, object: managedObjectContext, queue: OperationQueue.main) { (notification) in
            if self.isViewLoaded {
                if let dictionary = notification.userInfo {
                    print(dictionary["inserted"])

                    if let inserted = dictionary["inserted"]{
                        var location = [Location]()
                        location = inserted as! [Location]
                    }

                    if let deleted = dictionary["deleted"] {
                    }
                }
            }
        }
    }
}

Answer 1

数据不是数组，是集合。并使用适当的 key 访问数据。

var managedObjectContext: NSManagedObjectContext! {
    didSet {
        NotificationCenter.default.addObserver(forName: Notification.Name.NSManagedObjectContextObjectsDidChange, object: managedObjectContext, queue: OperationQueue.main) { (notification) in
            if self.isViewLoaded {
                if let dictionary = notification.userInfo {
                    print(dictionary[NSInsertedObjectsKey])

                    if let inserted = dictionary[NSInsertedObjectsKey] as? Set<Location> {
                        var location = Array(inserted)
                    }

                    if let deleted = dictionary[NSDeletedObjectsKey] {
                    }
                }
            }
        }
    }
}