尝试在 SwiftUI 中使用协议和 TabView：“Type 'any <Protocol>' 无法符合 'Hashable'”

Question

我正在尝试在 SwiftUI 的

TabView

中使用几个符合自定义协议的对象。问题是，当我编写下面的代码时，我在

TabView

:

上收到此错误

Type 'any Target' cannot conform to 'Hashable'

如何解决这个问题？我的代码如下：

protocol Target {
    var id: Int { get }
    var name: String { get }
}

struct Target1: Target {
    var id: Int = 1
    var name: String = "Target1"
}

struct Target2: Target {
    var id: Int = 2
    var name: String = "Target2"
}

struct Target3: Target {
    var id: Int = 3
    var name: String = "Target3"
}

struct ContentView: View {
    
    let targets: [any Target] = [Target1(), Target2(), Target3()]
    @State private var selectedTarget: any Target = Target1()
    
    var body: some View {
        NavigationStack {
            TabView(selection: $selectedTarget) { // This is where the error occurs.
                ForEach(targets, id: \.id) { target in
                    Text(target.name)
                }
            }
            .tabViewStyle(.page(indexDisplayMode: .always))
        }
    }
}

Answer 1

如果将

selectedTarget

的类型更改为

Target.id

的类型（换句话说，更改为

Int

），它就会起作用：

@State private var selectedTarget: Int = 1