在iPad上的SwiftUI中呈现ActionSheet

Question

我已经有了一个ActionSheet，可以在iPhone设备上正常显示。但它在iPad上崩溃。说它需要弹出窗口的位置。有人用过此代码吗？我正在使用iOS 13 beta 3和Xcode 11 beta3。（这使用的是一个表示ActionSheet的版本，该版本在beta 2中不可用）

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

Answer 1

最后，正如在 iOS 13.4 中测试的那样，这已经得到解决，至少在测试版中是这样。冲突约束警告仍然存在，但崩溃消失了。现在这是展示行动表的适当方式。

import SwiftUI

struct ContentView : View {
    @State var showSheet = false

    var body: some View {
        VStack {
            Button(action: {
                self.showSheet.toggle()
            }) {
                Text("Show")
            }
            .actionSheet(isPresented: $showSheet, content: { ActionSheet(title: Text("Hello"))
            })
        }
    }
}

struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Answer 2

遗憾的是，此错误尚未针对iOS 13的最终版本进行修复。在开发人员论坛上已提及该错误，我已经对此进行了反馈（FB7397761），但暂时需要使用一些解决方法。其他UI时UIDevice.current.userInterfaceIdiom == .pad。

作为记录，（无用的）异常消息是：

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's 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.'

解决方法是，此popSheet功能将在iPad和ActionSheet其他任何地方显示弹出框：

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's 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.'