如何在iOS 12中替换NSKeyedArchiver的初始化程序init(forWritingWith :)来编码CKRecord的元数据

let coder = NSKeyedArchiver()
/* encode stuff */
let data = coder.encodedData

这消除了对NSMutableData变体的需求,并且通过此更新,不推荐使用可变数据变体,这有利于更新的范例.所以而不是写作

let data = NSMutableData()
let coder = NSKeyedArchiver.init(forWriTingWith: data)
coder.requiresSecureCoding = true
record.encodeSystemFields(with: coder)
coder.finishEncoding()

你会写的

let coder = NSKeyedArchiver(requiringSecureCoding: truE)
record.encodeSystemFields(with: coder)
let data = coder.encodedData

不再需要手动分配.requiresSecureCoding和手动finishEncoding()调用.

请注意,只有在调用CKRecord.encodeSystemFields(带:)时才需要这种舞蹈,它显式地接受NSCoder以便仅编码自身的子集.在编码对象的一般情况下,您将使用the new NSKeyedArchiver.archivedData(withRootObject:requiringSecureCoding:) method：

let data = try NSKeyedArchiver.archivedData(withRootObject: /* object */,requiringSecureCoding: truE)

这相当于

let coder = NSKeyedArchiver(requiringSecureCoding: truE)
coder.encodeObject(/* object */,forKey: NSKeyedArchiveRootObjectKey)
let data = coder.encodedData