Question 130915 in Xcode Question posted in
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Xcode – SwiftUI ForEach loop not updating in real time

I’m using a ForEach to loop through an array of saved user input and display those, which displays everything correctly, unless I add a new input to this array, then the new item isn’t displayed unless I navigate to another View then come back.

I’ve tried everything, from changing .id with .self, but nothing works.

Any idea guys? Thank you!

EDIT: It looks like it’s my sheet that prevents my view from updating, I’ve tried simply adding the sheet code in my view and now the ForEach updates in real time, is there something I’m missing regarding how sheets could get in the way?

struct AnswersView: View {
@EnvironmentObject var vm: BrainstormViewModel
@Environment(.presentationMode) var presentationMode
@State var mBIndex: Int
@State var substitute: [String] = []
@State var showSheet: Bool = false
@State var updater: Bool = false
var body: some View {
    ScrollView {
        VStack(alignment: .leading) {
            Text("How could I...")
            Text(vm.brainstormArray[mBIndex].title)
                .font(.system(size: 32, weight: .bold, design: .rounded))
                .multilineTextAlignment(.leading)
            Button {
                showSheet.toggle()
            } label: {
                ButtonSubview(icon: "play.fill", text: "Continue brainstorm")
                    .environmentObject(BrainstormViewModel())
            }

            ForEach(vm.brainstormArray[mBIndex].answersArray, id: .self) { index in

                Text(index.name)
                    .font(.system(size: 20, weight: .bold, design: .rounded))
                    .padding(.top, 30)
                HStack {
                    Text(index.answer[0])

                        .padding()

                    Spacer()
                }

                .background(Color.MyTheme.orangeLight)
                .cornerRadius(16)
            }
        }

        .fullScreenCover(isPresented: $showSheet) {
            BrainstormView(mBIndex: mBIndex)
        }

        .navigationBarTitleDisplayMode(.inline)
    }
    .frame(maxWidth: .infinity)
    .padding()
    .background(Color.white)
}

}

Tags:

2

Answers


  1. 0

    The possible solution – but you have to try it in your code – is to make a @State variable that contains your array, and make that array a @Published variable in the view model. Then, listen to changes in that array and update the @State variable of your view.

    Here’s the idea:

    In the view model:

    class BrainstormViewModel: ObservableObject {
    ...
    @Published private(set) var brainstormArray: [WhateverType]
    ...
}

    In the view (scroll also to the bottom):

    struct AnswersView: View {
@EnvironmentObject var vm: BrainstormViewModel
@Environment(.presentationMode) var presentationMode
@State var mBIndex: Int
@State var substitute: [String] = []
@State var showSheet: Bool = false
@State var updater: Bool = false

// Here is the new variable
@State private var viewArray = [WhateverType]()

var body: some View {
    ScrollView {
        VStack(alignment: .leading) {
            Text("How could I...")
            Text(vm.brainstormArray[mBIndex].title)
                .font(.system(size: 32, weight: .bold, design: .rounded))
                .multilineTextAlignment(.leading)
            Button {
                showSheet.toggle()
            } label: {
                ButtonSubview(icon: "play.fill", text: "Continue brainstorm")
                    .environmentObject(BrainstormViewModel())
            }


            // Change the array over which the ForEach iterates, use the view variable
            ForEach(viewArray[mBIndex].answersArray, id: .self) { index in

                Text(index.name)
                    .font(.system(size: 20, weight: .bold, design: .rounded))
                    .padding(.top, 30)
                HStack {
                    Text(index.answer[0])

                        .padding()

                    Spacer()
                }

                .background(Color.MyTheme.orangeLight)
                .cornerRadius(16)
            }
        }

        .fullScreenCover(isPresented: $showSheet) {
            BrainstormView(mBIndex: mBIndex)
        }

        .navigationBarTitleDisplayMode(.inline)
    }
    .frame(maxWidth: .infinity)
    .padding()
    .background(Color.white)

    // Initialise the state variable
    .onAppear {
        viewArray = vm.brainstormArray
    }

    // Listen to changes in the view model
    .onChange(of: vm.brainstormArray) { array in
        viewArray = array
    }
}
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  2. 0

    wherever you change the data, insert:

    vm.objectWillChange.send()
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