如何预览依赖于PresentationMode的SwiftUI按钮？

我如何预览这个需要PresentationMode才能构建的按钮？ 该按钮在包含它的主视图中运行良好。它使用声明为以下内容的environment PresentationMode对象创建该按钮：

@Environment(\.presentationMode) var presentationMode:Binding<PresentationMode>

---

我认为PresentationMode应该声明为环境变量

那么就这样宣布吧

@Environment(\.presentationMode) var presentationMode

然后像这样改变它，因为它不再是一个绑定

Button(action: {
    self.presentationMode.wrappedValue.dismiss()

编辑：

下面是BackButton视图的预览示例/以及如何使用PresentationMode

struct MainView: View {
    var body: some View {
    
        NavigationView
        {
            VStack()
            {
                Text("Hello World")
                
                NavigationLink("Go to Detail View", destination: BackButton(color: .black))
        
            }.navigationBarTitle(Text("Main View"))
        }
    }
}


struct BackButton : View
{
    //Environment variable here
    @Environment(\.presentationMode) var presentationMode
    
    var color: Color
    
    var body: some View
    {
        Button(action: {
            //Dismiss the View
            self.presentationMode.wrappedValue.dismiss()
        }, label: { Image(systemName: "chevron.left")
          .scaleEffect(1.3)
          .foregroundColor(color)
          .offset(x: -17)
          .frame(width: 43, height: 43)
        })
    }
}

struct BackButton_Previews: PreviewProvider {
    static var previews: some View {
        //Preview here is working, no need to pass environment variable
        //Going back from this view in Preview won't work
        BackButton(color: .black)
    }
}

---

这就是它在普通代码中的工作方式。但我的问题是关于预演。在预览中，我无法创建button@onthemoon但是，您仍然可以使用BackButton（颜色：。黑色）执行预览。为什么在预览中需要该演示模式？我现在就知道了。您基本上是说将绑定传递到presentationMode是必要的，因为它可以在BackButton结构中声明为环境。伟大的谢谢。。我建议/并且经常读到您将其声明为环境。因此，无需使用绑定，在创建视图时必须设置绑定。预览将与环境一起工作我完全同意

struct MainView: View {
    var body: some View {
    
        NavigationView
        {
            VStack()
            {
                Text("Hello World")
                
                NavigationLink("Go to Detail View", destination: BackButton(color: .black))
        
            }.navigationBarTitle(Text("Main View"))
        }
    }
}


struct BackButton : View
{
    //Environment variable here
    @Environment(\.presentationMode) var presentationMode
    
    var color: Color
    
    var body: some View
    {
        Button(action: {
            //Dismiss the View
            self.presentationMode.wrappedValue.dismiss()
        }, label: { Image(systemName: "chevron.left")
          .scaleEffect(1.3)
          .foregroundColor(color)
          .offset(x: -17)
          .frame(width: 43, height: 43)
        })
    }
}

struct BackButton_Previews: PreviewProvider {
    static var previews: some View {
        //Preview here is working, no need to pass environment variable
        //Going back from this view in Preview won't work
        BackButton(color: .black)
    }
}