Question

我有一个包含NavigationView的视图A。 A通过激活NavigationLink推入ViewB。 B通过激活NavigationLink推动视图C。 C通过点击NavigationLink按下视图D。然后，D将视图显示为图纸。如果我关闭工作表，则当前的顶视图为B。出于某种原因，出现该工作表会弹出2个屏幕。

有人可以解释此行为，我该如何解决？我正在以某种方式猜测视图B中的导航链接（即推动视图C）被停用，但我不知道为什么

从我的测试来看，似乎在工作表出现时，ViewB被重新初始化，这将重新初始化我的vm，因此取消了链接。如何阻止视图重新初始化？

struct ViewA: View {
@SwiftUI.Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
@ObservedObject private var viewModel: ViewAVM

var body: some View {
    NavigationView {
        GeometryReader { fullView in
            ScrollView(.vertical, showsIndicators: false) {
                if !self.viewModel.loading {
                    VStack(alignment: .leading, spacing: 0) {
                        DetailsView(car: self.$viewModel.data)
                        Spacer(minLength: 20)
                        NavigationLink(destination: ViewB(rootActive: self.$viewModel.showB), isActive: self.$viewModel.showB) {
                            Button(action: {
                                self.viewModel.showB = true
                            }) {
                                SecondaryButtonView(enabled: true, title: "Go")
                            }
                        }.isDetailLink(false).padding([.leading, .trailing], 20)
                    }.frame(minHeight: fullView.size.height)
                }
            }
        }
        .navigationBarBackButtonHidden(true)
        .navigationBarTitle("View A")
        .navigationBarItems(leading: Button(action: {
            self.presentationMode.wrappedValue.dismiss()
        }) {
            Image("LeftArrow").renderingMode(.original)
        })
        .onAppear {
            self.viewModel.update()
        }
    }
    .navigationBarTitle("")
    .navigationBarHidden(true)
}

}

struct ViewBUI: View {
@SwiftUI.Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
@ObservedObject private var viewModel: ViewBVM
private let rootActive: Binding<Bool>
var body: some View {
    GeometryReader { fullView in
        ScrollView(.vertical, showsIndicators: false) {
            VStack(alignment: .leading, spacing: 0) {
                Text("").font(.regularParagraph).padding(.top, 15).padding(.bottom, 10)
                CustomEntryView()
                Spacer(minLength: 20)
                NavigationLink(destination: ViewC(rootActive: self.rootActive), isActive: self.$viewModel.showC) {
                    Button(action: {
                        self.hideKeyboard()
                        self.viewModel.validate()
                    }) {
                        PrimaryButtonView(enabled: self.viewModel.valid, title: "Continue")
                    }.disabled(!self.viewModel.valid)
                }.isDetailLink(false).padding(.bottom, 16)
            }.padding([.leading, .trailing], 20).frame(minHeight: fullView.size.height)
        }
    }
    .navigationBarBackButtonHidden(true)
    .navigationBarTitle(viewModel.new ? "New" : "Old")
    .navigationBarItems(leading: Button(action: {
        self.viewModel.rootActive.wrappedValue = false
    }) {
        Image("LeftArrow").renderingMode(.original)
    })
}

}

struct ViewDUI: View {
@SwiftUI.Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
let isDriver: Bool
let car: Binding<Car?>
let rootActive: Binding<Bool>

var body: some View {
    GeometryReader { fullView in
        ScrollView(.vertical, showsIndicators: false) {
                VStack(alignment: .leading, spacing: 0) {
                    Text("").font(.regularParagraph).foregroundColor(Color.black).padding([.leading, .trailing], 20).padding(.top, 15)
                    CarDetailsView(car: self.car)
                    Spacer(minLength: 20)
                    if self.car.wrappedValue?.mot == true && self.car.wrappedValue?.taxed == true {
                        if self.isDriver {
                            Button(action: {
                                self.rootActive.wrappedValue = false
                            }) {
                                PrimaryButtonView(enabled: true, title: "Save")
                            }.padding(.bottom, 16).padding([.leading, .trailing], 20)
                        } else {
                            NavigationLink(destination: ViewE(rootActive: self.$viewModel.showB)) {
                                PrimaryButtonView(enabled: true, title: "Continue")
                            }.isDetailLink(false).padding(.bottom, 16).padding([.leading, .trailing], 20)
                        }
                    } else {
                        Button(action: {
                            self.presentationMode.wrappedValue.dismiss()
                        }) {
                            PrimaryButtonView(enabled: true, title: "")
                        }.padding(.bottom, 16).padding([.leading, .trailing], 20)
                    }
                }.frame(minHeight: fullView.size.height)
        }
    }
    .navigationBarBackButtonHidden(true)
    .navigationBarTitle("")
    .navigationBarItems(leading: Button(action: {
        self.presentationMode.wrappedValue.dismiss()
    }) {
        Image("LeftArrow").renderingMode(.original)
    })
}

}

struct ViewEUI: View {
@SwiftUI.Environment(\.presentationMode) private var presentationMode: Binding<PresentationMode>
private let rootActive: Binding<Bool>
private let isDriver: Bool
@State private var showingScanner = false
@State private var scanHandler: LicenseScanHandler!
@State private var scanCompleted = false

var body: some View {
    VStack(alignment: .leading, spacing: 0) {
        Text("")
            .font(.regularParagraph)
            .padding(.top, 15)
            .padding([.leading, .trailing], 20)
        ZStack(alignment: .topLeading) {
            VStack(alignment: .leading, spacing: 0) {
                Image("sample")
                    .resizable()
                    .aspectRatio(contentMode: .fit)
                    .padding(20)
            }
            .overlay(RoundedRectangle(cornerRadius: 3).stroke(Color.azure, lineWidth: 1))
            .background(Color.white.edgesIgnoringSafeArea(.all))
            .padding(.top, 12)
            Text("")
            .font(.tinyParagraph)
            .foregroundColor(.azure)
            .frame(width: 80, height: 24)
            .background(Color.white.edgesIgnoringSafeArea(.all))
            .cornerRadius(8)
            .overlay(RoundedRectangle(cornerRadius: 8).stroke(Color.azure, lineWidth: 1))
            .padding(.leading, 20)
        }
        .padding([.leading, .trailing], 40)
        .padding(.top, 16)
        Spacer(minLength: 20)
        Button(action: {
            self.showingScanner = true
        }) {
            PrimaryButtonView(enabled: true, title: "Scan")
        }.padding(.bottom, 16).padding([.leading, .trailing], 20)
        .sheet(isPresented: $showingScanner) {
            ScannerWrapper(handler: self.scanHandler)
        }
        NavigationLink(destination: InfoUI(), isActive: $scanCompleted) {
            Text("")
        }.isDetailLink(false)
    }
    .background(Color.offWhite.edgesIgnoringSafeArea(.all))
    .navigationBarBackButtonHidden(true)
    .navigationBarTitle("")
    .navigationBarItems(leading: Button(action: {
        self.presentationMode.wrappedValue.dismiss()
    }) {
        Image("LeftArrow").renderingMode(.original)
    })
    .onAppear {
        self.scanHandler = LicenseScanHandler(delegate: self)
    }
}

}

Answer 1

尽管没有记录，但我意识到在通过.sheet()将视图本身设置为“无详细信息视图”时显示.isDetailLink(false)会导致此问题。

我可以看到为什么视图似乎不是局部视图，但它不能显示图纸，因此该图纸实际上是由第一个局部视图显示的，这就是为什么在显示图纸之后它又回到该视图的原因

如果确实不需要将其作为详细信息链接，请尝试删除.isDetailLink(false)并找到其他解决方法。

呈现工作表会从NavigationView弹出视图

1 个答案: