SwiftUI中如何通过状态变量无需点击自动激活Menu？

SwiftUI的默认Menu组件没有公开API支持自动触发展开，不过可以通过两种方式实现需求：

方法一：用Popover模拟菜单（推荐，纯SwiftUI实现） #

直接用Popover替代Menu，通过绑定isEditing状态控制弹出/收起，完全复刻原菜单的内容和样式：

ZStack(alignment: .trailing) {
    HStack {
        TextField("00:00", text: $customTime, onEditingChanged: { editing in
            self.isEditing = editing
        })
        .textFieldStyle(.plain)
        Spacer()
        Image(systemName:  "timer")
            .resizable()
            .frame(width: 15, height: 15)
            .foregroundStyle((isHovered && !isEditing) ? Color(.darkGray) : (isEditing ? Color(.lightDarkerGreen) : Color(.gray)))
    }
    .padding(.vertical, 20)
    .padding(.horizontal, 16)
    .background(RoundedRectangle(cornerRadius: 12).strokeBorder((isHovered && !isEditing) ? Color(.darkGray) : (isEditing ? Color(.lightDarkerGreen) : Color(.gray)), lineWidth: 2))
    
    // 替换原Menu为Popover，绑定isEditing自动触发
    Button(action: {}) {
        EmptyView()
    }
    .frame(width: 50, height: 50)
    .background(Color.clear)
    .padding(.trailing, 5)
    .popover(isPresented: $isEditing, arrowEdge: .trailing) {
        // 原Menu的内容直接移到这里
        Section(header: Text("Sugestões")) {
            ForEach(timeStamps, id: \.self) { time in
                Button("\(String(time)) minutos") {
                    selectedSortByOption = time
                    customTime = formatTime(time)
                    // 选择后关闭Popover
                    isEditing = false
                }
            }
        }
        .padding(8)
        .frame(width: 200)
    }
}

说明：

• Popover的isPresented直接绑定isEditing，TextField进入编辑状态时自动弹出
• 可以通过arrowEdge设置箭头方向，匹配原菜单的位置
• 内部内容完全复用原Menu的结构，保持交互逻辑一致

方法二：桥接UIKit触发原生ContextMenu #

如果需要完全复用原生Menu的样式（比如系统级的圆角、动画），可以通过UIViewRepresentable桥接UIKit的UIContextMenuInteraction，手动触发菜单：

1. 创建触发视图 #

struct ContextMenuTriggerView: UIViewRepresentable {
    let menuItems: [UIMenuElement]
    @Binding var shouldShowMenu: Bool
    
    func makeUIView(context: Context.Context) -> UIView {
        let view = UIView()
        view.isUserInteractionEnabled = true
        let interaction = UIContextMenuInteraction(delegate: context.coordinator)
        view.addInteraction(interaction)
        return view
    }
    
    func updateUIView(_ uiView: UIView, context: Context.Context) {
        // 当shouldShowMenu变为true时触发菜单
        if shouldShowMenu {
            let interaction = uiView.interactions.first(where: { $0 is UIContextMenuInteraction }) as? UIContextMenuInteraction
            interaction?.performMenuPresentation(for: uiView.bounds)
            // 触发后重置状态，避免重复触发
            DispatchQueue.main.async {
                shouldShowMenu = false
            }
        }
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(parent: self)
    }
    
    class Coordinator: NSObject, UIContextMenuInteractionDelegate {
        let parent: ContextMenuTriggerView
        
        init(parent: ContextMenuTriggerView) {
            self.parent = parent
        }
        
        func contextMenuInteraction(_ interaction: UIContextMenuInteraction, configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
            return UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { _ in
                UIMenu(title: "", children: self.parent.menuItems)
            }
        }
    }
}

2. 在原视图中使用 #

ZStack(alignment: .trailing) {
    // 原HStack和TextField部分保持不变
    HStack {
        TextField("00:00", text: $customTime, onEditingChanged: { editing in
            self.isEditing = editing
        })
        .textFieldStyle(.plain)
        Spacer()
        Image(systemName:  "timer")
            .resizable()
            .frame(width: 15, height: 15)
            .foregroundStyle((isHovered && !isEditing) ? Color(.darkGray) : (isEditing ? Color(.lightDarkerGreen) : Color(.gray)))
    }
    .padding(.vertical, 20)
    .padding(.horizontal, 16)
    .background(RoundedRectangle(cornerRadius: 12).strokeBorder((isHovered && !isEditing) ? Color(.darkGray) : (isEditing ? Color(.lightDarkerGreen) : Color(.gray)), lineWidth: 2))
    
    // 使用自定义触发视图
    ContextMenuTriggerView(
        menuItems: timeStamps.map { time in
            UIAction(title: "\(time) minutos") { _ in
                selectedSortByOption = time
                customTime = formatTime(time)
            }
        },
        shouldShowMenu: $isEditing
    )
    .frame(width: 50, height: 50)
    .background(Color.clear)
    .padding(.trailing, 5)
}

说明：

• 通过performMenuPresentation方法手动触发原生ContextMenu
• 菜单选项通过UIMenuElement数组传递，保持和原SwiftUI菜单一致的交互
• 触发后需要重置shouldShowMenu状态，避免TextField编辑状态变化时重复触发

内容的提问来源于stack exchange，提问作者Leonardo Mota