SwiftUI-NavigationLink中的NavigationBar在视图中迅速显示然后消失

Posted 2023-01-14

我有一个ContentView，其中包含一个NavigationView，该NavigationView导致一个DestinationView。我想在ContentView中隐藏导航栏，但在DestinationView中显示它。为了将其隐藏在ContentView中，我将navigationBarHidden设置为true，并给navigationBarTitle一个空字符串。在DestinationView中，我将navigationBarHidden设置为false，并为其指定标题“ DestinationView”。

如果我运行该项目并点击NavigationLink，DestinationView将显示NavigationBar，但在视图出现后会迅速将其隐藏。有人可以帮我吗？

struct ContentView: View 
    var body: some View 
        NavigationView 
            ZStack 
                Color.red.frame(maxWidth: .infinity, maxHeight: .infinity)
                NavigationLink(destination: DestinationView()) 
                    ZStack 
                        Color.green.frame(width: 200, height: 200)
                        Text("Tap me")
                    
                
            
            .navigationBarTitle("")
            .navigationBarHidden(true)
        
    


struct DestinationView: View 
    var body: some View 
        List 
            Text("1")
            Text("2")
        
        .navigationBarTitle("DestinationView")
        .navigationBarHidden(false)
    

答案

您需要使用变量来实现此目标并将其与目标绑定

struct ContentView: View 
         @State var isNavigationBarHidden: Bool = true
        var body: some View 
            NavigationView 

                ZStack 
                    Color.red.frame(maxWidth: .infinity, maxHeight: .infinity)
                    NavigationLink(destination: DestinationView(isNavigationBarHidden: self.$isNavigationBarHidden)) 
                        ZStack 
                            Color.green.frame(width: 200, height: 200)
                            Text("Tap me")
                        
                    

                
                .navigationBarHidden(self.isNavigationBarHidden)
                .navigationBarTitle("")
                .onAppear 
                    self.isNavigationBarHidden = true
                
            
        
    

    struct DestinationView: View 
        @Binding var isNavigationBarHidden: Bool
        var body: some View 
            List 
                Text("1")
                Text("2")
            
            .navigationBarTitle("DestinationView")

            .onAppear 
                self.isNavigationBarHidden = false
            
        
    

另一答案

我遇到了这个错误，最终使用UIViewControllerRepresentable包装了一个控制器，该控制器将导航栏的隐藏状态设置为其viewDidAppear方法：

struct ContentView: View 
    var body: some View 
        NavigationView 
            ZStack 
                Color.red.frame(maxWidth: .infinity, maxHeight: .infinity)
                NavigationLink(destination: DestinationView()) 
                    ZStack 
                        Color.green.frame(width: 200, height: 200)
                        Text("Tap me")
                    
                
            
            .navigationBarTitle("")
            .navigationBarHidden(true)
        
    


struct DestinationView: View 
    var body: some View 
        List 
            Text("1")
            Text("2")
        
        .navigationBarTitle("DestinationView")
        .navigationBarHidden(false)
        .background(HorribleHack())
    


struct HorribleHack: UIViewControllerRepresentable 
    func makeUIViewController(context: Context) -> HorribleHackViewController 
        HorribleHackViewController()
    

    func updateUIViewController(_ uiViewController: HorribleHackViewController, context: Context) 
    


class HorribleHackViewController: UIViewController 
    override func viewDidAppear(_ animated: Bool) 
        DispatchQueue.main.async 
            self.navigationController?.setNavigationBarHidden(false, animated: false)