无法在SwiftUI中使用ForEach和CoreData将数据正确传递到模式表示 [英] Can’t pass data correctly to modal presentation using ForEach and CoreData in SwiftUI

问题描述

我试图将某些对象的数据从对象列表传递到模式表，从CoreData中获取数据。

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

问题是，无论我单击列表中的哪个对象，详细信息视图中都只会显示最后添加的数据形式的对象。

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.

删除对象的方法也一样-不管我要删除哪个对象，最后一个对象都会一直删除。

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

问题使用NavigationLink消失了，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

视图堆栈中应该只有一张纸，所以只需将其移出 ForEach ，如下所示

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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