So everything works well and this app is about they way I want it, except that I want to have the ability in the DiceRollListView to delete a dice roll... I can get that to work only while on that view, but when I go back to the view, the change is not saved, nor does it save after closing to the app. None of that code code I used to delete/save is shown as it just was not working... Can someone point me in the right direction? I have tried various methods used from other apps in the HWS course but I am missing something...I think I have been looking at it too long. I have the full GitHub available as well at: https://github.com/VulcanCCIT/DiceFun

Code below:

I have a data model of:

import SwiftUI

struct RollResult: Identifiable, Codable {
  var id = UUID()
  var lastDice1RollValue: Int
  var lastDice2RollValue: Int
  var lastRollTotal: Int

  init(lastDice1RollValue: Int, lastDice2RollValue: Int, lastRollTotal: Int) {
    self.lastDice1RollValue = lastDice1RollValue
    self.lastDice2RollValue = lastDice2RollValue
    self.lastRollTotal = lastRollTotal
  }
}

I have a DiceRollListView like this:

struct DiceRollListView: View {
  var diceRolls: [RollResult]

  var body: some View {
    Text("Past Dice Results")
      .font(.title2).bold()

    List(diceRolls) { roll in
      HStack {
        Text("Dice 1: ")
          .fontWeight(.bold)
        Text("\(roll.lastDice1RollValue)")
          .font(.title2)
          .foregroundColor(.blue)
          .fontWeight(.bold)

        Text("Dice 2: ")
          .fontWeight(.bold)
        Text("\(roll.lastDice2RollValue)")
          .font(.title2)
          .foregroundColor(.green)
          .fontWeight(.bold)

        Text("Roll Total: ")
          .fontWeight(.bold)
        Text("\(roll.lastRollTotal)")
          .font(.title2)
          .foregroundColor(.red)
          .fontWeight(.bold)

      }
    }
  }
}

#Preview {
  DiceRollListView(diceRolls: [RollResult(lastDice1RollValue: 3, lastDice2RollValue:4, lastRollTotal: 7)])
}

I have a ContentView-ViewController like this:

import AVFoundation
import Foundation
import SwiftUI
import UIKit

extension ContentView {
  @MainActor class ViewModel: ObservableObject {

    let savePath = FileManager.documentsDirectory.appendingPathComponent("SavedRolls.json")

    @Published var feedback = UIImpactFeedbackGenerator(style: .rigid)

    @Published private(set) var diceRolls: [RollResult]
    @Published var showingDiceRollList = false

    //@Published var segmentColor: UIColor = .blue

    @Published var rollTotal = 2
    @Published var degree = 0.0
    @Published var degree2 = 0.0
    @Published var angle: Double = 0
    @Published var bounce = false

    @Published var dice1OffsetValX: CGFloat = 0
    @Published var dice1OffsetValY: CGFloat = 0
    @Published var dice2OffsetValX: CGFloat = 0
    @Published var dice2OffsetValY: CGFloat = 0

    @Published var diceVal1 = 1
    @Published var diceVal2 = 1

    @Published var timeRemaining = 0
    @Published var isActive = false

    @Published var diceRollSound: AVAudioPlayer!

    init() {
      do {
        let data = try Data(contentsOf: savePath)
        diceRolls = try JSONDecoder().decode([RollResult].self, from: data)
      } catch {
        diceRolls = []
      }
    }

    func save() {
      do {
        let data = try JSONEncoder().encode(diceRolls)
        try data.write(to: savePath, options: [.atomicWrite, .completeFileProtection])
      } catch {
        print("Unable to save data.")
      }
    }

    func updateRolls() {
      rollTotal = diceVal1 + diceVal2
      diceRolls.append(RollResult(lastDice1RollValue: diceVal1, lastDice2RollValue: diceVal2, lastRollTotal: rollTotal))
      print(diceRolls)

      save()
    }
  }
}

ContentView like this:

import AVFoundation
import SwiftUI

enum PickerColor: String, Hashable, Identifiable, CustomStringConvertible, CaseIterable {
  case red
  case yellow
  case green
  case blue
  case purple

  var id: String { rawValue }
  var description: String { rawValue.capitalized }

  var color: Color {
    switch self {
      case .red: .red
      case .yellow: .yellow
      case .green: .green
      case .blue: .blue
      case .purple: .purple
    }
  }
}

struct ContentView: View {
  @StateObject private var viewModel = ViewModel()

  @Environment(\.scenePhase) var scenePhase
  @AppStorage("soundOn") var soundOn = false
  @AppStorage("pickerColor") var pickerColor: PickerColor = .red

  var timer = Timer.publish(every: 0.2, on: .main, in: .common).autoconnect()

  var body: some View {

    NavigationStack {
      VStack {
        Picker(selection: $pickerColor, content: {
          ForEach(PickerColor.allCases) { color in
            Text(color.description)
              .tag(color)
          }
        }, label: EmptyView.init)
        .pickerStyle(.segmented)
        .tint(pickerColor.color)                                            .onAppear(perform: updatePickerColor)
        .onChange(of: pickerColor,
                  updatePickerColor)
        .frame(height: 50)
        Text("Roll Total: \(viewModel.rollTotal)")
          .frame(width: 200)
          .background(.red)
          .foregroundColor(.white)
          .font(.title.bold())
          .ignoresSafeArea()
          .clipShape(Capsule())
          .padding()
        HStack {
          Image("\(pickerColor)\(viewModel.diceVal1)")
            .resizable()
            .frame(width: 125, height:  125)
            .shadow(color: pickerColor.color.opacity(0.4), radius: 10, x: 10, y: -12)
            .rotation3DEffect(.degrees(viewModel.degree), axis: (x: 0, y: 0, z: 1))
            .offset(x: viewModel.bounce ? 0 : viewModel.dice1OffsetValX, y: viewModel.bounce ? 100 : viewModel.dice1OffsetValY)
            .animation(Animation.interpolatingSpring(stiffness: 50, damping: 15), value: viewModel.diceVal1)

          Image("\(pickerColor)\(viewModel.diceVal2)")
            .resizable()
            .frame(width: 125, height:  125)
            .shadow(color: pickerColor.color.opacity(0.4), radius: 10, x: 10, y: -12)
            .rotation3DEffect(.degrees(viewModel.degree2), axis: (x: 0, y: 0, z: 1))
            .offset(x: viewModel.bounce ? 0 : viewModel.dice2OffsetValX, y: viewModel.bounce ? 100 : viewModel.dice2OffsetValY)
            .animation(.interpolatingSpring(stiffness: 50, damping: 15), value: viewModel.diceVal2)
        } //HStack
        .frame(width: 350, height:550)
      }
      .toolbar {
        ToolbarItem(placement: .navigationBarLeading) {
          Button {
            soundOn.toggle()
          } label: {
            Label("Sound On/Off",  systemImage: soundOn ? "speaker.wave.3" :  "speaker.slash")
          }
        }
        ToolbarItemGroup(placement: .navigationBarTrailing) {
          NavigationLink(destination: DiceRollListView(diceRolls: viewModel.diceRolls)) {
            Image(systemName: "dice")
          }
        }
      }
      .padding()
    }//nav
    .onReceive(timer) { time in
      print(viewModel.isActive)
      guard viewModel.isActive else { return }

      if viewModel.timeRemaining > 0 {
        viewModel.timeRemaining -= 1
        viewModel.diceVal1 = Int.random(in: 1...6)
        viewModel.diceVal2 = Int.random(in: 1...6)

        viewModel.dice1OffsetValX = CGFloat.random(in: -30...30)
        viewModel.dice1OffsetValY = CGFloat.random(in: -250...150)
        viewModel.dice2OffsetValX = CGFloat.random(in: -30...30)
        viewModel.dice2OffsetValY = CGFloat.random(in: -275...150)

        if soundOn { viewModel.feedback.impactOccurred() }

        print(viewModel.timeRemaining)
        print(viewModel.dice1OffsetValX)
        print(viewModel.dice1OffsetValY)
      }
      if viewModel.timeRemaining == 1 { viewModel.isActive = false

        print("timerstopped")
        viewModel.updateRolls()
      }
    }
    .onChange(of: scenePhase) { //newPhase in
      if scenePhase == .active {
        viewModel.isActive = true
      } else {
        viewModel.isActive = false
      }
    }

    Spacer()

    Button("Roll Dice!") {
      viewModel.isActive = true
      viewModel.dice1OffsetValX = CGFloat.random(in: -40...40)
      viewModel.dice1OffsetValY = CGFloat.random(in: -275...275)
      viewModel.dice1OffsetValX = CGFloat.random(in: -40...40)
      viewModel.dice1OffsetValY = CGFloat.random(in: -275...275)

      spin()
      viewModel.bounce.toggle()
      viewModel.degree += 360
      viewModel.degree2 += 360
      viewModel.angle += 45
    }
    .padding()
    .background(.blue)
    .foregroundColor(.white)
    .clipShape(Capsule())
  }

  func spin() {

    if soundOn { playSounds("DiceRollCustom1.wav") }
    viewModel.timeRemaining = 10
    print(viewModel.timeRemaining)
  }

  func playSounds(_ soundFileName : String) {
    guard let soundURL = Bundle.main.url(forResource: soundFileName, withExtension: nil) else {
      fatalError("Unable to find \(soundFileName) in bundle")
    }

    do {
      viewModel.diceRollSound = try AVAudioPlayer(contentsOf: soundURL)
    } catch {
      print(error.localizedDescription)
    }
    viewModel.diceRollSound.play()
  }

  func updatePickerColor() {
    let appearance = UISegmentedControl.appearance(for: .current)  // <- here
    appearance.selectedSegmentTintColor = UIColor(pickerColor.color)
  }
}

#Preview {
  ContentView()
}

FileManager like this:

import Foundation

extension FileManager {
  static var documentsDirectory: URL {
    FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
  }
}