关闭包含在 UIHostingController 中的 SwiftUI 视图

Question

我已经将我的登录视图控制器重写为 SwiftUI View。该SignInView被包裹在一UIHostingController子类中（final class SignInViewController: UIHostingController<SignInView> {}），并且被呈现模态，全屏，当符号是必要英寸

一切正常，除了我不知道如何SignInViewController从SignInView. 我试过添加：

@Environment(\.isPresented) var isPresented

在SignInView并将其分配给false当登录成功，但这并没有出现与UIKit的互操作到。我怎样才能关闭视图？

Answer 1

我发现了另一种似乎效果很好的方法，并且感觉比其他一些方法更简洁。脚步：

1. dismissAction向 SwiftUI 视图添加一个属性：

struct SettingsUIView: View {
    var dismissAction: (() -> Void)
    ...
}    

2. dismissAction当你想关闭视图时调用：

Button(action: dismissAction ) {
    Text("Done")
}

3. 当您呈现视图时，为其提供一个解除处理程序：

let settingsView = SettingsUIView(dismissAction: {self.dismiss( animated: true, completion: nil )})
let settingsViewController = UIHostingController(rootView: settingsView )

present( settingsViewController, animated: true )

Answer 2

更新：来自 iOS 15 beta 1 的发行说明：

isPresented、PresentationMode 和新的 DismissAction 操作会关闭从 UIKit 呈现的托管控制器。(52556186)

我最终找到了一个比提供的更简单的解决方案：

final class SettingsViewController: UIHostingController<SettingsView> {
    required init?(coder: NSCoder) {
        super.init(coder: coder, rootView: SettingsView())
        rootView.dismiss = dismiss
    }

    func dismiss() {
        dismiss(animated: true, completion: nil)
    }
}

struct SettingsView: View {
    var dismiss: (() -> Void)?
    
    var body: some View {
        NavigationView {
            Form {
                Section {
                    Button("Dimiss", action: dismiss!)
                }
            }
            .navigationBarTitle("Settings")
        }
    }
}

Answer 3

此处提供的所有答案对我都不起作用，可能是因为参考资料较弱。这是我想出的解决方案：

创建视图和 UIHostingController：

let delegate = SheetDismisserProtocol()
let signInView = SignInView(delegate: delegate)
let host = UIHostingController(rootView: AnyView(signInView))
delegate.host = host
// Present the host modally 

SheetDismisserProtocol：

class SheetDismisserProtocol: ObservableObject {
    weak var host: UIHostingController<AnyView>? = nil

    func dismiss() {
        host?.dismiss(animated: true)
    }
}

必须驳回的观点：

struct SignInView: View {
    @ObservedObject var delegate: SheetDismisserProtocol

    var body: some View {
        Button(action: {
            self.delegate.dismiss()
        })
    }
}

Answer 4

你可以只使用通知。

斯威夫特 5.1

在 SwiftUI 按钮处理程序中：

NotificationCenter.default.post(name: NSNotification.Name("dismissSwiftUI"), object: nil)

在 UIKit 视图控制器中：

NotificationCenter.default.addObserver(forName: NSNotification.Name("dismissSwiftUI"), object: nil, queue: nil) { (_) in
    hostingVC.dismiss(animated: true, completion: nil)
}

Answer 5

let rootView = SignInView();
let ctrl = UIHostingController(rootView: rootView);
ctrl.rootView.dismiss = {[weak ctrl] in
    ctrl?.dismiss(animated: true)
}
present(ctrl, animated:true, completion:nil);

注意：ctrl.rootView.dismiss不是rootView.dismiss

Answer 6

另一种方法（在我看来相对更容易）是UIViewController在您的中有一个可选的属性类型，SwiftUI view然后将其设置为将呈现UIHostingController的SwiftUI视图控制器，它将包装您的视图。

一个简单的设置视图：

struct SettingsView: View {
    
    var presentingVC: UIViewController?
    
    var body: some View {
        Button(action: {
            self.presentingVC?.presentedViewController?.dismiss(animated: true)
        }) {
            Text("Dismiss")
        }
    }
}

然后，当您使用UIHostingController以下方法从视图控制器呈现此视图时：

class ViewController: UIViewController {

    private func presentSettingsView() {
        var view = SettingsView()
        view.presentingVC = self
        let hostingVC = UIHostingController(rootView: view)
        present(hostingVC, animated: true, completion: nil)
    }
}

现在，你可以在的作用看Button的SettingsView，我们要谈ViewController驳回它呈现视图控制器，这对我们来说将是UIHostingController一个包装SettingsView。

Answer 7

使用主机控制器演示器扩展环境值怎么样？它允许presentationMode在层次结构中的任何视图中使用，并且易于重用和可扩展。定义您的新环境值：

struct UIHostingControllerPresenter {
    init(_ hostingControllerPresenter: UIViewController) {
        self.hostingControllerPresenter = hostingControllerPresenter
    }
    private unowned var hostingControllerPresenter: UIViewController
    func dismiss() {
        if let presentedViewController = hostingControllerPresenter.presentedViewController, !presentedViewController.isBeingDismissed { // otherwise an ancestor dismisses hostingControllerPresenter - which we don't want.
            hostingControllerPresenter.dismiss(animated: true, completion: nil)
        }
    }
}

private enum UIHostingControllerPresenterEnvironmentKey: EnvironmentKey {
    static let defaultValue: UIHostingControllerPresenter? = nil
}

extension EnvironmentValues {
    /// An environment value that attempts to extend `presentationMode` for case where
    /// view is presented via `UIHostingController` so dismissal through
    /// `presentationMode` doesn't work.
    var uiHostingControllerPresenter: UIHostingControllerPresenter? {
        get { self[UIHostingControllerPresenterEnvironmentKey.self] }
        set { self[UIHostingControllerPresenterEnvironmentKey.self] = newValue }
    }
}

然后在需要时传递值，例如：

let view = AnySwiftUIView().environment(\.uiHostingControllerPresenter, UIHostingControllerPresenter(self))
let viewController = UIHostingController(rootView: view)
present(viewController, animated: true, completion: nil)
...

并享受使用

@Environment(\.uiHostingControllerPresenter) private var uiHostingControllerPresenter
...
uiHostingControllerPresenter?.dismiss()

你去的地方

@Environment(\.presentationMode) private var presentationMode
...
presentationMode.wrappedValue.dismiss() // .isPresented = false