无法在 SwiftUI 中使用 ForEach 和 CoreData 将数据正确传递给模态演示 [英] Can’t pass data correctly to modal presentation using ForEach and CoreData in SwiftUI

问题描述

我试图将某个对象的数据从对象列表传递到模式表，从 CoreData 获取数据.

Im trying to pass data of some object from list of objects to modal sheet, fetching data from CoreData.

问题是无论我点击列表中的什么对象，详细信息视图中都只显示最后添加的数据表单对象.

The problem is that no matter what object I click on in the list, only the data form last added object appears in the details view.

删除对象也是如此——不管我想删除什么对象，最后一个总是被删除.

The same goes for deleting the object - no matter what object I'm trying to delete, the last one is deleted all the time.

使用 NavigationLink 问题消失，但它不适合我.

Problem disappears using NavigationLink, but it is not suitable for me.

这是我的代码:

import SwiftUI

struct CarScrollView: View {

    @Environment(.managedObjectContext) var moc
    @FetchRequest(entity: Cars.entity(), sortDescriptors: []) var cars: FetchedResults<Cars>

    @State var showDetails = false

    var body: some View {
        VStack {
            ScrollView (.vertical, showsIndicators: false) {
                ForEach (cars, id: .self) { car in

                    Text("(car.text!)")
                        .onTapGesture {
                            self.showDetails.toggle()
                    }
                    .sheet(isPresented: self.$showDetails) { CarDetail(id: car.id, text: car.text)
                    }
                }
            }
        }
    }
}

推荐答案

视图栈中应该只有一张sheet，所以把它移出ForEach，如下图

There should be only one sheet in view stack, so just move it out of ForEach, like below

struct CarScrollView: View {

    @Environment(.managedObjectContext) var moc
    @FetchRequest(entity: Cars.entity(), sortDescriptors: []) var cars: FetchedResults<Cars>

    @State private var selectedCar: Car? = nil

    var body: some View {
        VStack {
            ScrollView (.vertical, showsIndicators: false) {
                ForEach (cars, id: .self) { car in

                    Text("(car.text!)")
                        .onTapGesture {
                            self.selectedCar = car
                    }
                }
            }
        }
        .sheet(item: self.$selectedCar) { car in
             CarDetail(id: car.id, text: car.text)
        }

    }
}

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