Ios SwiftUI 搜索栏和导航标题之间的空间太大

我正在开发一个代码太多的复杂应用程序，但我try 创建了一个包含必要运行代码的示例应用程序来解释我的问题.

假设我有一个带有按钮的内容视图，该按钮打开一个带有导航标题、搜索栏和按钮的模式/工作表(名为"Main View").在这个主视图中，搜索栏和导航标题被正确定位.当我用主视图点击按钮时，它会导航到另一个有搜索栏和导航标题的视图(名为"Sub View")，并最终会有一个后退按钮来导航回主视图.在这个子视图中，我看到导航标题和搜索栏的位置不正确，即导航标题和搜索栏之间有很多空间.

我不能找出它的原因和如何修复它.对此有什么 idea 或 idea 吗？是因为两个导航堆栈，即一个在SampleAppApp struct 中，另一个在MainView struct 中吗？

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import SwiftUI
import Foundation
import Combine

@main
struct SampleAppApp: App {
    var body: some Scene {
        WindowGroup {
            NavigationStack {
                ContentView()
            }
        }
    }
}

struct ContentView: View {
    @State private var showModal: Bool = false
    var body: some View {
        VStack {
            Button("Click ME", action: { self.showModal.toggle() })
        }
        .sheet(isPresented: $showModal) {
            ZStack {
                Color(red: 0.95, green: 0.95, blue: 0.97)
                MainView(isPresented: $showModal).padding(.top, 15.0)
            }
        }
    }
}

// MARK: Code for Main View after "Click ME" is clicked
struct MainView: View {
    @State private var searchText = ""
    let searchTextPublisher = PassthroughSubject<String, Never>()

    /// Set to true when the panel is displayed. Dismisses the panel when set to false.
    var isPresented: Binding<Bool>
    @State private var showSubView: Bool = false

    var body: some View {
        NavigationStack {
            ZStack {
                Color(red: 0.95, green: 0.95, blue: 0.97).edgesIgnoringSafeArea(.all)
                VStack {
                    VStack {
                        Button("Tap to open sub-view", action: {
                            self.showSubView.toggle()
                        }).padding(.top, 20.0)
                    }
                    .navigationDestination(isPresented: $showSubView) {
                        SubView()
                    }
                    
                    MainViewSearchResultListAndNavTitle()
                    .searchable(
                        text: $searchText,
                        placement: .navigationBarDrawer(displayMode: .always),
                        prompt: "search"
                    )
                    .onChange(of: searchText) { newText in
                        searchTextPublisher.send(newText) /// Publishes when a search term is changed. This is used to debounce the search.
                    }
                    Spacer()
                }
                .frame(maxWidth: .infinity, maxHeight: .infinity)
                .background(Color(red: 0.95, green: 0.95, blue: 0.97))
            }
        }
        .presentationDetents([.large])
        .interactiveDismissDisabled(true)
        .presentationBackgroundInteraction(.enabled)
    }
}

/// Shows search bar and search results list.
struct MainViewSearchResultListAndNavTitle: View {
    var body: some View {
        VStack {
            // Contains search results list
        }
        .toolbar(content: {
            ToolbarItem(placement: .navigationBarLeading) {
                Text("Main View")
                    .bold()
                    .font(.largeTitle)
                    .padding(.bottom, 15.0)
            }
        })
        .toolbarBackground(Color(red: 0.95, green: 0.95, blue: 0.97), for: .navigationBar)
        .toolbarBackground(.visible, for: .navigationBar)
    }
}

// MARK: Code for Sub View after "Tap to open sub-view" is clicked. This view will have back button to go back to 2nd view i.e. "Main View".
struct SubView: View {
    var body: some View {
        ZStack {
            Color(red: 0.95, green: 0.95, blue: 0.97).edgesIgnoringSafeArea(.all)
            VStack {
                SubViewSearchResultsListAndNavTitle()
                .searchable(
                    text: .constant(""),
                    placement: .navigationBarDrawer(displayMode: .always),
                    prompt: "search"
                )
                Spacer()
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
            .background(Color(red: 0.95, green: 0.95, blue: 0.97))
        }
    }
}

private struct SubViewSearchResultsListAndNavTitle: View {
    var body: some View {
        VStack {
            // Contains search results list for sub view.
        }
        .toolbar(content: {
            ToolbarItem(placement: .principal) {
                Text("Sub view").bold()
                    .font(.title)
                    .padding(.bottom, 15.0)
            }
        })
        .toolbarBackground(Color(red: 0.95, green: 0.95, blue: 0.97), for: .navigationBar)
        .toolbarBackground(.visible, for: .navigationBar)
        .navigationBarBackButtonHidden(true)
    }
}

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