此方法将取消存档sks文件，并将其初始化为调用该文件的任何SKNode子类。这意味着您可以将文件作为SKNode取消存档（因此根节点将是SKNode）并将其作为子级添加到场景中。您也可以将文件归档为GameScene或任何SKNode子类。

extension SKNode {
    class func unarchiveFromFile(file : NSString) -> SKNode? {
        if let path = NSBundle.mainBundle().pathForResource(file, ofType: "sks") {
            var sceneData = NSData(contentsOfFile: path, options: .DataReadingMappedIfSafe, error: nil)!
            var archiver = NSKeyedUnarchiver(forReadingWithData: sceneData)

            archiver.setClass(self.classForKeyedUnarchiver(), forClassName: "SKScene")
            let scene = archiver.decodeObjectForKey(NSKeyedArchiveRootObjectKey) as SKNode
            archiver.finishDecoding()
            return scene
        } else {
            return nil
        }
    }
}

像这样使用它：

let scene = GameScene.unarchiveFromFile("GameScene")! as GameScene

要么

let levelStuff = SKNode.unarchiveFromFile("Level 1")!
self.addChild(levelStuff)