【发布时间】：2017-11-28 11:59:52
【问题描述】：
我在尝试解码这个 json 时收到此错误：
[{
"id": "76f22c25-cee7-4c7a-94fa-1fb85720f580",
"purchaseDate": "2012-04-05T19:03:43Z",
"title": "azare",
}, {
"id": "9b4b9f7d-382f-4555-9eaa-97939b13633f",
"purchaseDate": "2012-04-05T19:02:46Z",
"title": "Chocolat",
}, {
"id": "02a0aa06-2d0c-4ab9-aaaa-af7dee7b4845",
"purchaseDate": "2012-09-24T17:39:52Z",
"title": "Some thing",
}]
致命错误：“试试！”表达式意外引发错误：Swift.DecodingError.typeMismatch(Swift.Double, Swift.DecodingError.Context(codingPath: [Foundation.(_JSONKey in _12768CA107A31EF2DCE034FD75B541C9)(stringValue: "Index 0", intValue: Optional(0)), MyApp.Purchase.CodingKeys.purchaseDate], debugDescription: "预期解码 Double 但找到一个字符串/数据 相反。”，基础错误：无））：文件 /BuildRoot/Library/Caches/com.apple.xbs/Sources/swiftlang/swiftlang-900.0.69.2/src/swift/stdlib/public/core/ErrorType.swift， 第 181 行
My code:
//Purchase+CoreDataClass.swift
@objc(Purchase)
public class Purchase: NSManagedObject, Codable {
enum CodingKeys: String, CodingKey {
case id
case title
case purchaseDate
}
required convenience public init(from decoder: Decoder) throws {
var context : NSManagedObjectContext = MyAppCoreDataManager.sharedInstance.persistentContainer.viewContext
guard let entity = NSEntityDescription.entity(forEntityName: "Purchase", in: context!) else { fatalError() }
self.init(entity: entity, insertInto: context!)
let container = try decoder.container(keyedBy: CodingKeys.self)
self.title = try container.decodeIfPresent(String.self, forKey: .title)
self.id = try container.decodeIfPresent(String.self, forKey: .id)
self.purchaseDate = try! container.decodeIfPresent(Date.self, forKey: .purchaseDate)
}
public func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(id, forKey: .id)
try container.encode(title, forKey: .title)
try container.encode(purchaseDate, forKey: .purchaseDate)
}
}
// Purchase+CoreDataProperties.swift
extension Purchase {
@nonobjc public class func fetchRequest() -> NSFetchRequest<Purchase> {
return NSFetchRequest<Purchase>(entityName: "Purchase")
}
@NSManaged public var id: String?
@NSManaged public var title: String?
@NSManaged public var purchaseDate: Date?
}
//CALL
let decoder = JSONDecoder()
decoder.dataDecodingStrategy = .base64
let purchases = try decoder.decode([Purchase].self, from: value)
If i remove "purchaseDate" everything works correctly
【问题讨论】：
-
在 json 中 purchaseDate 是字符串格式，与数据模型中的数据类型 Date 不匹配。
标签： swift nsmanagedobject codable