菜单未更新(SwiftUI 错误?) [英] Menu not updating (SwiftUI bug?)

问题描述

我正在使用 macOS Montery Beta 4 和 Xcode 13 Beta 4，我想我在 SwiftUI 中发现了一个错误.

I'm using macOS Montery Beta 4 along with Xcode 13 Beta 4, and I think I've discovered a bug in SwiftUI.

当使用 CommandGroup 以及根据条件启用/禁用的按钮时，CommandGroup 不会更新.CommandMenu 但是.

When using a CommandGroup along with a button that is enabled/disabled based on a condition, the CommandGroup doesn't update. CommandMenu does however.

1. 创建一个新的 SwiftUI macOS 项目
2. 将以下代码粘贴到 App 文件中:

class Test: ObservableObject {
    @Published var num = 0
}

@main
struct TestApp: App {
    @StateObject private var test = Test()
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(test)
        }
        .commands {
            CommandGroup(after: .newItem) {
                Button(action: {}) {
                    Text("Test menu item")
                }
                .disabled(test.num == 0)
            }
        }
    }
}

1. 将以下代码粘贴到 ContentView 文件中:

struct ContentView: View {
    @EnvironmentObject var test: Test
    
    var body: some View {
        Button(action: {
            test.num += 1
        }) {
            Text(String(test.num) + " ---------")
        }
    }
}

1. 运行应用程序，然后单击File 菜单.您应该看到测试菜单项"已按预期禁用.
2. 点击按钮.这只是将数字加 1.但是，测试菜单项"会增加 1.仍然被禁用，即使 test.num != 0.

1. Run the app, and click on the File menu. You should see that "Test menu item" is disabled as expected.
2. Click on the button. This simply increments a number by 1. However, "Test menu item" is still disabled, even though test.num != 0.

问题是，将 CommandGroup 替换为 CommandMenu("Test menu") 修复了它.

The thing is, replacing the CommandGroup with CommandMenu("Test menu") fixes it.

该应用程序所做的只是有一个菜单项，如果数字为零，则该菜单项将被禁用.按下按钮使该数字不为零，但菜单项保持禁用状态.

All the app does is have a menu item that is disabled if a number is zero. Pressing the button makes that number not zero, but the menu item stays disabled.

有人能重现这个吗，这是我的错误吗?

Is anybody able to reproduce this, and is this a bug on my part?

推荐答案

@George_E 答案的一个小变化，是这样的:

a minor variation of @George_E answer, is this:

 CommandGroup(after: .newItem) {
       TestView(test: test)
 }
 
 struct TestView: View {
     @ObservedObject var test: Test
  
     var body: some View {
         Button(action: {}) {
             Text("Test menu item")
         }
         .disabled(test.num == 0)
     }
 }

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