SwiftUI从ForEach中的按钮打开工作表并传递参数[复制]

下面的swiftUI代码在iOS13上运行良好,但在iOS14的测试中,我在尝试显示模式表时遇到了由强制展开选项引起的致命错误。据我所知,工作表永远不应该为selectedModel提供nil值,因为showingDetails只有在分配selectedModel后才会变为true?

struct SpeakerBrandMenu: View {
    var filteredSpeakers: [Speaker] {
        // An array of Speaker objects
        }
        
    @State var selectedModel: Speaker?
    @State private var showingDetails = false

    var body: some View {
        List{       
        ForEach(filteredSpeakers) { speaker in
            HStack {
                Button(action: {
                    self.selectedModel = speaker
                    self.showingDetails = true
                }) {
                    SpeakerModelRow(speaker: speaker).contentShape(Rectangle())
                }
                .buttonStyle(PlainButtonStyle())

                Spacer()
                
                Button(
                //unrelated
                ).padding(5)
              }
            }
        } .sheet(isPresented: self.$showingDetails) { SpeakerDetailView(speaker: self.selectedModel!, showSheet: self.$showingDetails).environmentObject(self.favoriteSpeakers).environmentObject(self.settings)}
               
          .navigationBarTitle(Text(brand), displayMode: .inline)
    }
}

有趣的是,如果我把它拆开 speaker: self.selectedModel ?? filteredSpeakers[0] 它的行为与预期完全一致:第一次按下任何菜单项时,第一个项目将传递给工作表,但在关闭工作表并选择另一个项目时,它每次都会显示正确的项目。因此,分配选定模型的按钮似乎试图在分配时间之前显示工作表。