导航栏隐藏在 SwiftUI 中不起作用

Question

我有三观。我想隐藏第三个视图中的导航栏。即使我给.navigationBarHidden(true)导航栏显示！

我找不到我做错的地方。我附上了我的代码和下面的截图。

Xcode 版本 - 11.1

struct ContentViewOne: View {
    var body: some View {
        NavigationView {
            ZStack {
                
                Color.yellow.edgesIgnoringSafeArea(.all)
                VStack(spacing: 20) {
                    Text("View One")
                    
                    NavigationLink(destination: ContentViewTwo()) {
                        Text("Navigate to View Two")
                            .foregroundColor(.white)
                            .padding()
                            .background(Color.red)
                    }
                }
            }
            .navigationBarTitle("View One")
        }
    }
}

struct ContentViewTwo: View {
    var body: some View {
        
        ZStack {
            Color.green.edgesIgnoringSafeArea(.all)
            VStack(spacing: 20) {
                Text("View Two")
                NavigationLink(destination: ContentViewThree()) {
                    Text("Navigate to View Three")
                        .foregroundColor(.white)
                        .padding()
                        .background(Color.red)
                }
            }
        }
        .navigationBarTitle("View Two")
    }
}

struct ContentViewThree: View {
    var body: some View {
        ZStack {
            Color.gray.edgesIgnoringSafeArea(.all)
            Text("View Three")
        }
        .navigationBarTitle("View Three")
        .navigationBarHidden(true)
        .navigationBarBackButtonHidden(true)
    }
}

Answer 1

注意：（出于某种原因它在某些情况下有效）SwiftUI需要您需要.navigationBarTitlefor.navigationBarHidden才能正常工作。

NavigationView {
    ScrollView() {
     ......
    }.  
    .navigationBarTitle("") //this must be empty
    .navigationBarHidden(true)
    .navigationBarBackButtonHidden(true)
}

Answer 2

我尝试了多种解决方案，包括 UINavigationControllerDelegate，但似乎没有什么可以使导航栏永久隐藏。直到我尝试了 KVO :)

因此，如果您想要永久解决方案，请使用以下命令：

struct NoBarNavigationView<Content: View>: View {

    private let content: Content

    init(@ViewBuilder content: () -> Content) {
        self.content = content()
    }

    var body: some View {
        NavigationView {
            content
                .introspectNavigationController { (UINavigationController) in
                    NavigationControllerDelegate.shared.becomeDelegate(of: UINavigationController)
                }
        }
    }
}

class NavigationControllerDelegate: NSObject {

    static let shared = NavigationControllerDelegate()

    func becomeDelegate(of navigationController: UINavigationController) {
        navigationController.isNavigationBarHidden = true
        navigationController.navigationBar.isHidden = true
        navigationController.navigationBar.addObserver(self, forKeyPath: "alpha", options: .new, context: nil)
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        // This is necessary to ensure the UINavigationBar remains hidden
        if let navigationBar = object as? UINavigationBar {
            navigationBar.isHidden = true
        }
    }

}

快乐编码！

编辑：正如评论中指出的，我正在使用：

import Introspect

GitHub 链接