Question

我正在创建一个简单的核心数据应用程序，代码上没有错误，但是在预览中或在物理设备上运行时，它在启动时崩溃。日志是

CrashOnLaunchError：AppName应用在启动时崩溃

更新预览时，应用“ AppName”崩溃。在〜/ Library / Logs / DiagnosticReports中查找崩溃日志以获取更多详细信息。

在物理设备上运行时，在类定义的AppDelegate中 xcode引发线程1：“ NSFetchedResultsController的实例需要具有排序描述符的提取请求”

Error Domain = FBSOpenApplicationServiceErrorDomain代码= 1“请求打开“ com.company.AppName”失败。” UserInfo = {BSErrorCodeDescription = RequestDenied， NSLocalizedDescription =打开“ com.company.AppName”的请求失败。，NSUnderlyingError = 0x7f89753f7aa0 {Error Domain = SketchBoard 代码= 1“应用程序无法启动” UserInfo = {NSLocalizedDescription =应用程序无法启动， NSLocalizedFailureReason =该操作无法完成。交易失败。子交易失败：（子级交易），NSUnderlyingError = 0x7f8975356fd0 {错误 Domain = BSTransactionError Code = 1“交易失败。孩子事务失败：（子交易）” UserInfo = {NSLocalizedFailureReason =交易失败。儿童事务失败：（子事务），precipitating-error =错误 Domain = BSTransactionError Code = 1“交易失败。孩子事务失败：（子级交易）“ UserInfo = {NSLocalizedFailureReason =交易失败。子事务失败：（子交易），precipitating-error =错误 Domain = BSTransactionError Code = 1“交易失败。场景更新失败（场景更新失败）” UserInfo = {NSLocalizedFailureReason =交易失败。场景更新失败（场景更新失败），error-reason =场景更新失败， error-description =场景更新失败， transaction = }，错误原因=子事务，错误描述=子事务失败：， transaction = }，错误原因=子事务，错误描述=子事务失败：， transaction = }}}}， FBSOpenApplicationRequestID = 0xddf3，NSLocalizedFailureReason = The 服务代表拒绝了该请求（SketchBoard.SketchBoardSystemService）。}

重新启动计算机和XCODE后，显示另一个错误

AppLaunchTimeoutError：无法启动应用程序“ PreviewAgentBundle（标识符：“ com.company.AppName”，URL：file：/// Users / UserName / Library / Developer / Xcode / DerivedData / AppName％3F-fnttuytzfpshkcdpkeevdewzrypc / Build / Intermediates .noindex / Previews / AppName％3F / Products / Debug-iphonesimulator / AppName％3F.app，executableSubpath：“ AppName”，版本：AnyHashable（9781），signingInformation：可选（UVPreviewPipeline.CodeSigningInformation（标识符：Optional（“ com.company .AppName“），标识：无，hasGetTaskAllow：false，isSandboxed：false）））”“在合理的时间

应用程序“ PreviewAgentBundle（标识符：“ com.company.AppName”，网址：file：///Users/UserName/Library/Developer/Xcode/DerivedData/AppName%3F-fnttuytzfpshkcdpkeevdewzrypc/Build/Intermediates.noindex/Previews /Appname%3F/Products/Debug-iphonesimulator/AppName%3F.app，executableSubpath：“AppName”，版本：AnyHashable（9781），signingInformation：可选（UVPreviewPipeline.CodeSigningInformation（标识符：Optional（“ com.company.AppName”）），身份：零，hasGetTaskAllow：假，isSandboxed：假）））”在15秒钟内未在“ iPhone 11 Pro Max”上启动。

捆绑包标识符：com.company.AppName 设备UDID：UUID 请求UUID：UUID screenID：0

我有3页，

内容视图

import SwiftUI

struct ContentView: View {
    
    @Environment(\.managedObjectContext) var managedObjectContext
    @FetchRequest(fetchRequest: PostCodeCore.getPostcode()) var postCodes:FetchedResults<PostCodeCore>
    
    @State private var enteredPostcode = ""
    var body: some View {
        NavigationView {
       
           
            
                Button(action: {
                    
                    TextField("Postcode", text: self.$enteredPostcode)
                    let postCodeCore = PostCodeCore(context: self.managedObjectContext)
                    postCodeCore.postcodeObject = self.enteredPostcode
                    do {
                        try self.managedObjectContext.save()
                    }catch{
                        print(error)
                    }
                    
                    self.enteredPostcode = ""
                    
                }) {
                    Text("Proceed")
                }
            ForEach(self.postCodes) {PostCodeCore in
                PostCodeView(postcode: PostCodeCore.postcodeObject!)
            }
           
          
          
        }.navigationBarTitle("Hello")
       
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

PostCodeView


import Foundation
import SwiftUI

struct PostCodeView: View {
    var postcode: String = ""
    var body: some View {
        Text(postcode)
    }
}

struct PostCodeView_Previews: PreviewProvider {
    static var previews: some View {
        PostCodeView(postcode: "WD6 3PU")
    }
}

和PostCodeCore

import Foundation
import CoreData

public class PostCodeCore:NSManagedObject, Identifiable {
    @NSManaged public var postcodeObject:String?
}

extension PostCodeCore {
    static func getPostcode() -> NSFetchRequest<PostCodeCore> {
        let request:NSFetchRequest<PostCodeCore> = PostCodeCore.fetchRequest() as! NSFetchRequest<PostCodeCore>
    
        return request
    }
}

和我的XCDataModel看起来像这样 https://imgur.com/a/xOV5U3f

任何帮助将不胜感激，谢谢

线程1：“ NSFetchedResultsController的实例需要具有排序描述符的提取请求”

0 个答案: