为什么我不能访问CloudKit中CKRecord的createdAt字段

Question

我无法在CloudKit中访问我的记录类型的createdAt系统字段。我尝试过将"createdAt"one_answers"creationDate"作为CKQueryOperation.desiredKeys参数的参数。无论哪种方式，当我使用CKRecord.object(forKey:(访问createdAt字段时，我都会得到nil。

这是我检索记录的代码：

entries = [Entry]()
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: DatabaseNameStrings.recordTypeEntry, predicate: predicate)
let sortDescriptor = NSSortDescriptor(key: DatabaseNameStrings.recordFieldKeyCreationDate, ascending: true)
query.sortDescriptors = [sortDescriptor]
let queryOperation = CKQueryOperation(query: query)
queryOperation.desiredKeys = [DatabaseNameStrings.recordFieldKeyCreationDate, DatabaseNameStrings.fieldNameText]
queryOperation.recordFetchedBlock = {
(record: CKRecord) in
let entry = Entry(ckRecord: record)
self.entries.append(entry)
}
queryOperation.queryCompletionBlock = {
(cursor: CKQueryOperation.Cursor?, error: Error?) in
if let error = error {
print(error.localizedDescription)
} else {
DispatchQueue.main.async {
self.tableView.reloadData()
}
if let cursor = cursor {
let innerQueryOperation = CKQueryOperation(cursor: cursor)
innerQueryOperation.desiredKeys = queryOperation.desiredKeys
innerQueryOperation.recordFetchedBlock = queryOperation.recordFetchedBlock
innerQueryOperation.queryCompletionBlock = queryOperation.queryCompletionBlock
queryOperationQueue.addOperation(queryOperation)
}
}
}
queryOperationQueue.addOperation(queryOperation)

以下是保存密钥的字符串变量的代码：

enum DatabaseNameStrings {
static let recordTypeEntry = "Entry"
static let fieldNameCreatedAt = "createdAt"
static let fieldNameText = "text"
static let recordFieldKeyCreationDate = "creationDate"
}

以下是我访问createdAt字段的代码：

print(ckRecord.object(forKey: DatabaseNameStrings.recordFieldKeyCreationDate) as Any)
print(ckRecord.object(forKey: DatabaseNameStrings.fieldNameCreatedAt) as Any)

Answer 1

我使用CKRecord.creationDate而不是CKRecord.object(forKey:(.