如何仅使用 ForEach 而不是 List 从动态范围中删除

Question

我找不到从 ForEach 循环中使用的动态数组中删除的方法。我一直在寻找没有运气。许多答案使用 List 或在其 ForEach 中没有绑定。而且我不想使用列表，因为它很难完全定制它的设计。

以下是从数组中添加和删除元素的示例代码。该数组用于显示玩家的动态列表。

在解开 ForEach 循环中的可选项后，移除一个播放器会产生一个超出范围的索引。

import SwiftUI

struct GameRecapView: View {

    @State private var game = Game(players: [Player(name: "Steph"),Player(name: "Kim")])
    @State private var shape = Shape.circle

    var body: some View {
        VStack {
            ForEach(self.game.players ,id: \.id) { player in
                PlayerView(
                    player: self.$game.players[self.game.players.firstIndex(where: {$0.id == player.id})!],
                    shape: self.$shape)
            }
            Spacer()
            Button(action: {
                self.toggleShape()
            }) {
                Text("Change shape")
            }
            HStack {
                Button(action: {
                    self.addPlayer(player: Player(name: "Eddye"))
                }) {
                    Text("+")
                }
                Button(action: {
                    self.removeLastPlayer()
                }) {
                    Text("-")
                }
            }
        }
    }

    func toggleShape(){
        if self.shape == .circle {
            self.shape = .square
        } else {
            self.shape = .circle
        }
    }

    func addPlayer(player : Player) {
        self.game.players.append(player)
    }

    func removeLastPlayer(){
        self.game.players.removeLast()
    }

    func removeItems(at offsets: IndexSet) {
        self.game.players.remove(atOffsets: offsets)
    }

}

struct PlayerView: View {

    @Binding var player : Player
    @Binding var shape : Shape

    var letters = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t"]

    var body: some View {

        VStack {
            ZStack{
                Text(String(self.player.name.first!.uppercased()))
                if shape == .square {
                    Rectangle().stroke().frame(width: 50, height: 50)
                } else {
                    Circle().stroke().frame(width: 50, height: 50)
                }

            }

            Button(action: {
                self.player.name = self.letters.randomElement()!
            }) {
                Text("Change Name")
            }

        }
    }
}

struct Game {
    var players : [Player]
}

struct Player : Identifiable {
    var id = UUID()
    var name : String
}

enum Shape {
    case
    circle ,
    square
}

struct GameRecapView_Previews: PreviewProvider {
    static var previews: some View {
        GameRecapView()
    }
}

Answer 1

看看这个：（测试和工作）

始终致力于单一的事实来源（正如苹果所说的那样），而不是副本。确保您的更改将由 ObservableObject 完成。

class Data : ObservableObject {

    @Published var game = Game(players: [Player(name: "Steph"),Player(name: "Kim")])
}

struct GameRecapView: View {

    @EnvironmentObject var data : Data

    @State private var shape = Shape.circle

    var body: some View {
        VStack {
            ForEach(self.data.game.players ,id: \.id) { player in
                PlayerView(
                    player: self.data.game.players[self.data.game.players.firstIndex(where: {$0.id == player.id})!],
                    shape: self.$shape)
            }
            Spacer()
            Button(action: {
                self.toggleShape()
            }) {
                Text("Change shape")
            }
            HStack {
                Button(action: {
                    self.addPlayer(player: Player(name: "Eddye"))
                }) {
                    Text("+")
                }
                Button(action: {
                    self.removeLastPlayer()
                }) {
                    Text("-")
                }
            }
        }
    }

    func toggleShape(){
        if self.shape == .circle {
            self.shape = .square
        } else {
            self.shape = .circle
        }
    }

    func addPlayer(player : Player) {
        self.data.game.players.append(player)
    }

    func removeLastPlayer(){
        self.data.game.players.removeLast()
    }

    func removeItems(at offsets: IndexSet) {
        self.data.game.players.remove(atOffsets: offsets)
    }

}

struct PlayerView: View {

    @EnvironmentObject var data : Data

    var player : Player
    @Binding var shape : Shape

    var letters = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t"]

    var body: some View {

        VStack {
            ZStack{
                Text(String(self.player.name.first!.uppercased()))
                if shape == .square {
                    Rectangle().stroke().frame(width: 50, height: 50)
                } else {
                    Circle().stroke().frame(width: 50, height: 50)
                }

            }

            Button(action: {
                let playerIndex = self.data.game.players.firstIndex(where: {$0.id == self.player.id})
                self.data.game.players[playerIndex!].name = self.letters.randomElement()!
            }) {
                Text("Change Name")
            }

        }
    }
}

struct Game {
    var players : [Player]
}

struct Player : Identifiable {
    var id = UUID()
    var name : String
}

enum Shape {
    case
    circle ,
    square
}

struct ContentView: View {

    var body : some View {
        Text("wtf")
    }
}

struct GameRecapView_Previews: PreviewProvider {
    static var previews: some View {
        GameRecapView().environmentObject(Data())
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}