@Environment(\.dismiss) bug 导致弹出视图在 iOS 15 中加载自身的新版本

Question

导航到 INCR: 3 并点击导航栏后退按钮或关闭按钮，您会注意到再次调用相同的视图，但这次是新版本，因为 和onAppear firstLoad = true是rand不同的值。

如果您注释掉@Environment(\.dismiss) var dismiss，dismiss()一切都会像 iOS 14 中那样按预期工作。此问题也会发生在@Environment(\.presentationMode) var presentationMode

不确定这是一个错误还是我犯了一个愚蠢的错误，但这个问题给我的应用程序带来了很多问题，因为我必须能够以编程方式关闭视图，因此任何输入都会受到赞赏。

struct DetailView: View {
    
    @Environment(\.dismiss) var dismiss
    
    @State var isPresenting = false
    
    @State var incrInt = 0
    
    @State var firstLoad = true
    
    @State var rand = Int.random(in: 1..<500)
    
    var body: some View {
        
        Text("INCR: \(incrInt) RAND: \(rand)")
        
        Button("NAVIGATE"){
            isPresenting = true
        }
        Button("DISMISS"){
           dismiss()
        }
        
        .onAppear(perform: {
            
            if firstLoad{
                print("ON APPEAR FIRST LOAD")
                print(incrInt)
                print(rand)
                print("\n")
                firstLoad = false
            }
        })
        
        NavigationLink(destination: DetailView(incrInt: (incrInt + 1)), isActive: $isPresenting){}
        
    }
}

struct ContentView: View {
    var body: some View {
        NavigationView{
            VStack{
                DetailView()
            }
        }
    }
}

视频链接

https://i.imgur.com/qpu7NT7.​​mp4

更新 1：ViewModel 真相来源

class DetailViewModel: ObservableObject {
    
    @Published var isPresenting = false
    
    var incr: Int
    
    var rand = Int.random(in: 1..<500)
    
    init(incr: Int){
        
        self.incr = incr
        
        print("INIT FIRST LOAD")
        print(incr)
        print(rand)
        print("\n")
    }
    
}

struct DetailView: View {
    
    @Environment(\.dismiss) var dismiss
    
    @StateObject var detailViewModel: DetailViewModel
    
    var body: some View {
        
        Text("INCR: \(detailViewModel.incr) RAND: \(detailViewModel.rand)")
        
        
        Button("NAVIGATE"){
            detailViewModel.isPresenting = true
        }
        Button("DISMISS"){
            dismiss()
        }
        
        
        NavigationLink(destination: DetailView(detailViewModel: DetailViewModel(incr: (detailViewModel.incr + 1))), isActive: $detailViewModel.isPresenting){}
         
        
    }
}

struct ContentView: View {
    var body: some View {
        NavigationView{
            VStack{
                DetailView(detailViewModel: DetailViewModel(incr: 0))
            }
        }
    }
}

Answer 1

我通过添加.navigationViewStyle(.stack)到NavigationView. 我认为这是 iOS 上的默认导航视图样式，但也许在 iOS 15 中发生了变化。