问题描述
我有一个非常简单的应用程序，您应该可以在其中存储电影院、电影和演员。我首先使用非持久存储创建了它，以便我可以测试一切是否运行良好。
import SwiftUI
import CoreData
struct ContentView: View {
@Environment(\.managedobjectContext) private var viewContext
@FetchRequest(
sortDescriptors: [NSSortDescriptor(keyPath: \Cinema.name,ascending: true)],animation: .default)
private var items: FetchedResults<Cinema>
@State var showCinemaSheet = false
@State var cinemas = [CinemaDummy]()
var body: some View {
vstack {
Button("Create New Cinema") {
showCinemaSheet.toggle()
}.sheet(
isPresented: $showCinemaSheet,content: {
NewCinemaSheetView(
showCinemaSheet: $showCinemaSheet,cinemas: $cinemas)
})
Divider()
Text("List of Cinemas")
List {
ForEach(cinemas) { cinema in
vstack(alignment: .leading) {
HStack {
Text(cinema.name).font(.headline)
Spacer()
Text(cinema.location).font(.headline)
}
Text("\(cinema.movies.count) Movies")
}
}
}
}
}
}
struct NewCinemaSheetView: View {
@Binding var showCinemaSheet: Bool
@Binding var cinemas: [CinemaDummy]
@State var cinemaDummy = CinemaDummy()
@State var showMovieSheet = false
var body: some View {
vstack {
Button("Add new movie"){
showMovieSheet.toggle()
}.sheet(isPresented: $showMovieSheet,content: {
NewMovieSheetView(showMovieSheet: $showMovieSheet,movies: $cinemaDummy.movies)
})
TextField("Enter name of the cinema",text: $cinemaDummy.name).padding().border(Color.black,width: 1)
TextField("Enter location of the cinema",text: $cinemaDummy.location).padding().border(Color.black,width: 1)
Divider()
Text("List of movies")
List{
ForEach(cinemaDummy.movies) { movie in
vstack {
Text(movie.title)
Text("\(movie.actors.count) Actors")
}
}
}
Divider()
HStack {
Button("Save") {
cinemas.append(cinemaDummy)
showCinemaSheet.toggle()
}.padding()
Button("Cancel") {
showCinemaSheet.toggle()
}.padding()
}
}
}
}
struct NewMovieSheetView: View {
@Binding var showMovieSheet: Bool
@Binding var movies: [MovieDummy]
@State var showActorSheet = false
@State var movieDummy = MovieDummy()
var body: some View {
vstack {
Button("Add New Actor") {
showActorSheet.toggle()
}.sheet(isPresented: $showActorSheet,content: {ActorViewSheetView(
showActorSheet: $showActorSheet,actors: $movieDummy.actors
)})
TextField("Enter tile of movie",text: $movieDummy.title).padding().border(Color.black,width: 1)
TextField("Enter budget of movie",text: $movieDummy.budget).padding().border(Color.black,width: 1)
Divider()
Text("list of actors in this movie")
List{
ForEach(movieDummy.actors) { actor in
HStack {
Text(actor.firstName)
Text(actor.lastName)
}
}
}
Divider()
HStack {
Button("Add") {
movies.append(movieDummy)
showMovieSheet.toggle()
}.padding()
Button("Cancel") {
showMovieSheet.toggle()
}.padding()
}
}
}
}
struct ActorViewSheetView: View {
@Binding var showActorSheet: Bool
@Binding var actors: [ActorDummy]
@State var actorDummy = ActorDummy()
var body: some View {
vstack {
TextField("Enter first name of actor",text: $actorDummy.firstName)
.padding()
.border(Color.black,width: 1)
TextField("Enter last name of actor",text: $actorDummy.lastName)
.padding()
.border(Color.black,width: 1)
Divider()
Divider()
HStack {
Button("Add") {
actors.append(actorDummy)
showActorSheet.toggle()
}.padding()
Button("Cancel") {
showActorSheet.toggle()
}.padding()
}
}
}
}
这些是创建的模型：
import Foundation
struct CinemaDummy: Identifiable {
var id = UUID()
var name = ""
var location = ""
var movies = [MovieDummy]()
}
struct MovieDummy: Identifiable {
var id = UUID()
var title = ""
var budget = ""
var actors = [ActorDummy]()
}
struct ActorDummy: Identifiable {
var id = UUID()
var firstName = ""
var lastName = ""
}
现在我想保护数据持久化，但我无法做到这一点。我尝试在 xcdatamodeld 中创建模型，然后尝试通过彼此链接关系。
起初我想让 Xcode 为我完成所有工作，并让 Codegen 在“类定义”上工作，但它不起作用。 我通过“手动”设置 Codegen 并尝试添加处理 NSSet 的方法。 我通过（xcdatamodeld 中的所有选定模型）编辑器创建的文件 -> 创建 NSManagedobject Sublass 但这也不能运行。
在将近两周的时间里，我花了几天时间将这个项目连接到 CoreData，但没有任何帮助。
Persistence-manager 几乎是开箱即用的 Xcode-Manager：
import CoreData
struct PersistenceController {
static let shared = PersistenceController()
static var preview: PersistenceController = {
let result = PersistenceController(inMemory: true)
let viewContext = result.container.viewContext
do {
try viewContext.save()
} catch {
let nsError = error as NSError
fatalError("Unresolved error \(nsError),\(nsError.userInfo)")
}
return result
}()
let container: NSPersistentContainer
init(inMemory: Bool = false) {
container = NSPersistentContainer(name: "Cinematic")
if inMemory {
container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
}
container.loadPersistentStores(completionHandler: { (storeDescription,error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error),\(error.userInfo)")
}
})
}
}
我的问题是： - 有没有办法将这个项目连接到 CoreData？ - 我可以通过“类定义”设置 Codegen 还是我必须手动完成所有这些工作？ - 如何处理 NSSet？
解决方法
暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！
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