ios - 具有可转换属性的 CoreData 在保存时失败
问题描述
我想使用 CoreData 并将自定义类属性保存在其中一个实体中。这样做的方法似乎是使用Transformable:
然后我尝试添加一个元素并将其另存为:
import UIKit;
import CoreData;
public class EntityData: NSObject, NSSecureCoding
{
public static var supportsSecureCoding: Bool { true }
public func encode(with coder: NSCoder) {
coder.encode(self.name, forKey: "name");
}
public required init?(coder: NSCoder) {
self.name = coder.decodeObject(forKey: "name") as? String;
}
var name: String?;
init(name: String?) {
self.name = name;
}
}
class ViewController: UIViewController {
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(_: animated);
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext;
let entity = Entity(context: context);
entity.id = URL(string: "google.com");
entity.data = EntityData(name: "Foo");
do {
try context.save();
} catch {
print("While saveing: \(error)");
}
}
}
这失败了:
2021-09-30 13:12:58.865312+0400 tmpCoreData[5815:170015] [error] error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034f6040> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034f6040> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
2021-09-30 13:12:58.865530+0400 tmpCoreData[5815:170015] [error] error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
CoreData: error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
2021-09-30 13:12:58.865983+0400 tmpCoreData[5815:170015] [error] error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034e4300> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034e4300> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
2021-09-30 13:12:58.866158+0400 tmpCoreData[5815:170015] [error] error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
CoreData: error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
2021-09-30 13:12:58.866558+0400 tmpCoreData[5815:170015] [error] error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034ec0c0> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034ec0c0> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
2021-09-30 13:12:58.900366+0400 tmpCoreData[5815:170015] [error] error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
CoreData: error: -executeRequest: encountered exception = <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo = (null)
2021-09-30 13:12:58.912131+0400 tmpCoreData[5815:170015] [error] error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034f83c0> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
CoreData: error: SQLCore dispatchRequest: exception handling request: <NSSQLSaveChangesRequestContext: 0x6000034f83c0> , <shared NSSecureUnarchiveFromData transformer> threw while encoding a value. with userInfo of (null)
While saveing: Error Domain=NSCocoaErrorDomain Code=134060 "A Core Data error occurred."
我不确定我做错了什么。这就是我拥有的所有代码,我没有添加任何其他内容。
解决方案
可转换属性需要符合NS(Secure)Coding
(不是Codable
!)的类和归档对象的实现。注意NSSecureUnarchiveFromData
错误。
在 Swift 世界中,考虑将属性声明为String
,将对象编码为 JSONCodable
并添加计算属性以进行无缝转换。
推荐阅读
- python - 如何从缩短的 tiktok URL 中提取用户帐户名称和视频 ID?
- python - 如何使用python openpyxl删除excel中的row = 2
- ios - 将项目从 Xcode 10.3 迁移到 Xcode 11.5 时出错
- javascript - 在 html 中“获取”多个 xml 文件
- powershell - 在powershell中用某些文本字符串替换更多文本字符串
- jenkins - 将构建参数导出到共享库
- c++ - 从类成员函数转换为类 C 函数指针
- java - 更新包含彼此的 ArrayLists?
- rest - URL / API 架构最佳实践
- flutter - 无法从静态方法调用 Flutter Stateful Widget 的 setState