如何解决 unarchiveObject(withFile:) 的弃用问题

Question

在 iOS 12.1 中，unarchiveObject(withFile:) 已被弃用。
如何将NSKeyedUnarchiver.unarchiveObject(withFile: String) 转换为使用对NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data: Data) 或NSKeyedUnarchiver.unarchivedObject(ofClasses: [AnyClass] 的调用，来自：Data) 或NSKeyedUnarchiver.unarchivedObject(ofClass: NSCoding.Protocol, from: Data)？

我猜你必须有类似let fileData = try Data(contentsOf: URL) 的东西，然后使用其中一种方法来取消归档数据。但是，我无法弄清楚，并且折旧随附的文档没有帮助（至少对我而言）。

存档的数据相当简单——只是一个字符串数组（此代码定义的类NameToBeSaved的数组）：

class NameToBeSaved: NSObject, NSCoding {
var name: String

init(userEnteredName: String) {
    self.name = userEnteredName
    super.init()
}

func encode(with aCoder: NSCoder) {
    aCoder.encode(name, forKey: "name")
}

required init?(coder aDecoder: NSCoder) {
    name = aDecoder.decodeObject(forKey: "name") as! String
    super.init()
}

这里是调用 unarchiveObject(withFile:) 的代码 -

init() {
    if let archivedCategoryNames = NSKeyedUnarchiver.unarchiveObject(withFile: categoryNameArchiveURL.path) as? [NameToBeSaved] {
        allCategories += archivedCategoryNames
    } else {
        for category in starterCategories {
            let thisNewCategory = NameToBeSaved(userEnteredName: category)
            createNewCategory(thisNewCategory)
        }
        sortCategories()
    }
}

Answer 1

我不知道这是否是最好的解决方案，但这为我解决了转换问题（旧代码注释掉以供比较）：

    init() {

    do {
        let rawdata = try Data(contentsOf: categoryNameArchiveURL)
        if let archivedCategoryNames = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(rawdata) as! [NameToBeSaved]? {
            allCategories += archivedCategoryNames
        }
    } catch {
        print("Couldn't read file")
        for category in starterCategories {
            let thisNewCategory = NameToBeSaved(userEnteredName: category)
            createNewCategory(thisNewCategory)
        }
        sortCategories()
    }

/*        if let archivedCategoryNames = NSKeyedUnarchiver.unarchiveObject(withFile: categoryNameArchiveURL.path) as? [NameToBeSaved] {
            allCategories += archivedCategoryNames
        } else {
            for category in starterCategories {
                let thisNewCategory = NameToBeSaved(userEnteredName: category)
                createNewCategory(thisNewCategory)
            }
            sortCategories()
        }
 */
}

Answer 2

问题：取消归档 sks 文件以用作 SKEmitterNode。

旧方法，已弃用：

let filePath = Bundle.main.path(forResource: "myParticleEmitter", ofType: "sks")!
let burnerPathUnarchived = NSKeyedUnarchiver.unarchiveObject(withFile: burnerPath) as! SKEmitterNode

新方法：

do {
    let fileURL = Bundle.main.url(forResource: "myParticleEmitter", withExtension: "sks")!
    let fileData = try Data(contentsOf: fileURL)
    let unarchivedData = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(burnerData) as! SKEmitterNode
} catch {
    print("didn't work")
}

那么你可以这样做：

mySKEffectNode.addChild(unarchivedData)
mySKSpriteNode.addChild(mySKEffectNode)

Answer 3

Swift 5，去掉前缀 'NS' 并集中使用以备将来更改...

class KeyedUnarchiver : NSKeyedUnarchiver {
    open override class func unarchiveObject(with data: Data) -> Any? {
        do {
            let object = try NSKeyedUnarchiver.unarchivedObject(ofClasses: [NSObject.self], from: data)
            return object
        }
        catch let error {
            Swift.print("unarchiveObject(with:) \(error.localizedDescription)")
            return nil
        }
    }

    open override class func unarchiveObject(withFile path: String) -> Any? {
        do {
            let data = try Data(contentsOf: URL.init(fileURLWithPath: path))
            let object = try unarchivedObject(ofClasses: [NSObject.self], from: data)
            return object
        }
        catch let error {
            Swift.print("unarchiveObject(withFile:) \(error.localizedDescription)")
            return nil
        }
    }
}

Answer 4

作为suggested by Apple，我们应该使用FileManager来读取/写入归档文件。

func archiveURL() -> URL? {
    guard let documentURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first 
        else { return nil }

    return documentURL.appendingPathComponent("MyArchive.data")
}

func archive(customObject: CustomObject) {
    guard let dataToBeArchived = try? NSKeyedArchiver.archivedData(withRootObject: customObject, requiringSecureCoding: true), 
        let archiveURL = archiveURL() 
        else  {
        return
    }

    try? dataToBeArchived.write(to: archiveURL)
}

func unarchive() -> CustomObject? {
    guard let archiveURL = archiveURL(),
        let archivedData = try? Data(contentsOf: archiveURL),
        let customObject = (try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(archivedData)) as? CustomObject 
        else {
        return nil
    }

    return customObject
}