Представьте ActionSheet в SwiftUI на iPad

Я получил ActionSheet для представления на устройстве iPhone. Но он падает для iPad. Говорит, что нужно место для поповера. Кому-нибудь повезло с этим кодом? Я использую iOS 13 beta 3 и Xcode 11 beta 3. (Это использует версию представления ActionSheet, недоступную в beta 2)

import SwiftUI

struct ContentView : View {
    @State var showSheet = false

    var body: some View {
        VStack {
            Button(action: {
                self.showSheet.toggle()
            }) {
                Text("Show")
            }
            .presentation($showSheet) { () -> ActionSheet in
                ActionSheet(title: Text("Hello"))

            }
        }
    }
}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif

Ответы

Ответ 1

Это известная ошибка бета-версии. Просто жди исправления.

Ответ 2

К сожалению, эта ошибка не была исправлена в финальной версии iOS 13. Она упоминалась на форумах разработчиков, и я оставил отзыв (FB7397761), но пока что нужно обойти это, используя какой-то другой интерфейс, когда UIDevice.current.userInterfaceIdiom == .pad.

Для записи (бесполезное) сообщение об исключении:

2019-10-21 11:26:58.205533-0400 LOOksTape[34365:1769883] *** Terminating app due to uncaught exception 'NSGenericException', reason: 'Your application has presented a UIAlertController (<UIAlertController: 0x7f826e094a00>) of style UIAlertControllerStyleActionSheet from _TtGC7SwiftUI19UIHostingController… 
The modalPresentationStyle of a UIAlertController with this style is UIModalPresentationPopover. 
You must provide location information for this popover through the alert controller popoverPresentationController. 
You must provide either a sourceView and sourceRect or a barButtonItem.  
If this information is not known when you present the alert controller, you may provide it in the UIPopoverPresentationControllerDelegate method -prepareForPopoverPresentation.'

В качестве обходного пути эта функция popSheet будет отображать всплывающее окно на iPad и ActionSheet везде:

public extension View {
    /// Creates an 'ActionSheet' on an iPhone or the equivalent 'popover' on an iPad, in order to work around '.actionSheet' crashing on iPad ('FB7397761').
    ///
    /// - Parameters:
    ///     - isPresented: A 'Binding' to whether the action sheet should be shown.
    ///     - content: A closure returning the 'PopSheet' to present.
    func popSheet(isPresented: Binding<Bool>, arrowEdge: Edge = .bottom, content: @escaping () -> PopSheet) -> some View {
        Group {
            if UIDevice.current.userInterfaceIdiom == .pad {
                popover(isPresented: isPresented, attachmentAnchor: .rect(.bounds), arrowEdge: arrowEdge, content: { content().popover(isPresented: isPresented) })
            } else {
                actionSheet(isPresented: isPresented, content: { content().actionSheet() })
            }
        }
    }
}

/// A 'Popover' on iPad and an 'ActionSheet' on iPhone.
public struct PopSheet {
    let title: Text
    let message: Text?
    let buttons: [PopSheet.Button]

    /// Creates an action sheet with the provided buttons.
    public init(title: Text, message: Text? = nil, buttons: [PopSheet.Button] = [.cancel()]) {
        self.title = title
        self.message = message
        self.buttons = buttons
    }

    /// Creates an 'ActionSheet' for use on an iPhone device
    func actionSheet() -> ActionSheet {
        ActionSheet(title: title, message: message, buttons: buttons.map({ popButton in
            // convert from PopSheet.Button to ActionSheet.Button (i.e., Alert.Button)
            switch popButton.kind {
            case .default: return .default(popButton.label, action: popButton.action)
            case .cancel: return .cancel(popButton.label, action: popButton.action)
            case .destructive: return .destructive(popButton.label, action: popButton.action)
            }
        }))
    }

    /// Creates a '.popover' for use on an iPad device
    func popover(isPresented: Binding<Bool>) -> some View {
        VStack {
            ForEach(Array(buttons.enumerated()), id: \.offset) { (offset, button) in
                Group {
                    SwiftUI.Button(action: {
                        // hide the popover whenever an action is performed
                        isPresented.wrappedValue = false
                        // another bug: if the action shows a sheet or popover, it will fail unless this one has already been dismissed
                        DispatchQueue.main.async {
                            button.action?()
                        }
                    }, label: {
                        button.label.font(.title)
                    })
                    Divider()
                }
            }
        }
    }

    /// A button representing an operation of an action sheet or popover presentation.
    ///
    /// Basically duplicates 'ActionSheet.Button' (i.e., 'Alert.Button').
    public struct Button {
        let kind: Kind
        let label: Text
        let action: (() -> Void)?
        enum Kind { case 'default', cancel, destructive }

        /// Creates a 'Button' with the default style.
        public static func 'default'(_ label: Text, action: (() -> Void)? = {}) -> Self {
            Self(kind: .default, label: label, action: action)
        }

        /// Creates a 'Button' that indicates cancellation of some operation.
        public static func cancel(_ label: Text, action: (() -> Void)? = {}) -> Self {
            Self(kind: .cancel, label: label, action: action)
        }

        /// Creates an 'Alert.Button' that indicates cancellation of some operation.
        public static func cancel(_ action: (() -> Void)? = {}) -> Self {
            Self(kind: .cancel, label: Text("Cancel"), action: action)
        }

        /// Creates an 'Alert.Button' with a style indicating destruction of some data.
        public static func destructive(_ label: Text, action: (() -> Void)? = {}) -> Self {
            Self(kind: .destructive, label: label, action: action)
        }
    }
}