iOS15下Picker已打开时打开DatePicker出现异常Bug

在iOS15环境中，当Picker处于弹出状态时点击DatePicker，DatePicker仅标签变为蓝色（显示已打开状态），但选择界面无法弹出，再次点击也无任何响应。

报错信息 #

[Presentation] Attempt to present <_UIDatePickerContainerViewController: 0x7f78f8b049b0> on <_TtGC7SwiftUI29PresentationHostingControllerVS_7AnyView_: 0x7f78f301b800> (from <_TtGC7SwiftUI19UIHostingControllerVVS_P10$11d30daf821BridgedNavigationView8RootView_: 0x7f78f301aa00>) which is already presenting <_UIContextMenuActionsOnlyViewController: 0x7f78f399d810>.

最小复现代码（MRE） #

enum SomeCases: String, CaseIterable, Identifiable {
    case first = "First"
    case second = "Second"
    case third = "Third"
    case fourth = "Fourth"
    
    public var id: String { rawValue }
}

struct SwiftUIView: View {
    @State private var someCases: SomeCases = .first
    @State private var someDate: Date = .init()
    
    var body: some View {
        VStack (spacing: 150){
            Picker("First picker", selection: $someCases) {
                ForEach(SomeCases.allCases) { someCase in
                    Text(someCase.rawValue)
                        .fontWeight(.bold)
                }
            }
            
            DatePicker("Date picker", selection: $someDate)
        }
        .padding()
    }
}

解决方案（无需使用.sheet） #

问题根源是iOS15系统不允许同时弹出两个模态控制器，Picker打开时已占用present通道，导致DatePicker无法正常触发弹出。可以通过手动控制Picker的展示状态，在点击DatePicker前主动关闭Picker来解决：

修改后的代码如下：

enum SomeCases: String, CaseIterable, Identifiable {
    case first = "First"
    case second = "Second"
    case third = "Third"
    case fourth = "Fourth"
    
    public var id: String { rawValue }
}

struct SwiftUIView: View {
    @State private var someCases: SomeCases = .first
    @State private var someDate: Date = .init()
    @State private var isPickerPresented = false
    
    var body: some View {
        VStack (spacing: 150){
            // 自定义Picker触发区域，手动控制弹出状态
            Button(action: {
                isPickerPresented.toggle()
            }) {
                HStack {
                    Text("First picker")
                    Spacer()
                    Text(someCases.rawValue)
                        .foregroundColor(.blue)
                }
            }
            .popover(isPresented: $isPickerPresented) {
                List(SomeCases.allCases) { someCase in
                    Button(action: {
                        someCases = someCase
                        isPickerPresented = false
                    }) {
                        Text(someCase.rawValue)
                            .fontWeight(.bold)
                    }
                }
                .frame(maxHeight: 300)
            }
            
            DatePicker("Date picker", selection: $someDate)
                .onTapGesture {
                    // 点击DatePicker时先关闭Picker
                    isPickerPresented = false
                }
        }
        .padding()
    }
}

方案说明 #

• 用自定义按钮+popover替代系统默认Picker的弹出逻辑，通过isPickerPresented状态主动控制Picker的显示/隐藏
• 给DatePicker添加点击手势，触发时先关闭Picker，确保present通道空闲，DatePicker能正常弹出选择界面
• 完全不依赖.sheet，适配iOS15环境

内容的提问来源于stack exchange，提问作者Marko Markovic