Question

我目前正在尝试使用导航链接将值的数组传递到详细信息视图中。但是，每当我尝试传递数组时，指定用于显示导航链接的文本函数调用都会给我“表达式类型不明确且没有更多上下文的错误”错误。当我传递简单的单个值时，这不是问题，但是我需要能够在详细信息视图中显示数组中的每个元素。

struct Item: Identifiable{
           let id=UUID()
           let name:String
    }

    struct Group: Identifiable{
            let id:Int
            let thing:String
            let items:[Item]
    }

    //the "Item" objects are currently placeholders.
    var groups = [
        Group(id: 0,
              thing:"Tops",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 2,
              thing:"Jeans",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 3,
              thing:"Skirts",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 4,
              thing:"Shoes",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 5,
              thing:"Pajamas",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 6,
              thing:"Jackets",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 7,
              thing:"Hats",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")]),
        Group(id: 8,
              thing:"Jewelry",
              items:[Item(name:"first"), Item(name:"second"), Item(name:"third")])
    ]

var body: some View {
        List(groups){ group in
            NavigationLink(destination : ClosetDetailView(items: group.items)){
                        //location of error
                        Text(group.thing)
                }
            }
        .background(Color.pinkish)
        .navigationBarTitle("Categories")
        }
}

struct PlaceholderView:View {
    var body:some View{
        Text("placeholder")
    }
}

struct ClosetDetailView:View {
    struct Item: Identifiable{
              let id=UUID()
              let name:String
    }

    var items:[Item]

    var body : some View{
        List(items){ item in
            HStack{
                Text(item.name)
            }
        }
    }
}

Answer 1

首先，要启用到详细视图的导航，应将列表嵌入到NavigationView中：

struct ContentView: View {
    var body: some View {
        NavigationView {
            List(groups) { group in
                NavigationLink(destination: ClosetDetailView(items: group.items)) {
                    Text(group.thing)
                    .listRowBackground(Color.red)
                }
            }
            .navigationBarTitle("Categories")
        }

    }
}

如果将参数传递给函数时发生错误，通常会出现错误“表达式的类型是模棱两可的，没有更多上下文”。在这种情况下，您的壁橱详细视图需要一个Item数组。问题是您在ClosetDetailView内部和外部定义了一个项目结构。将项目传递到ClosetDetailView时发生此错误，可能会导致整个NavigationLink出错。删除ClosetDetailView中的Struct，错误消失：

struct ClosetDetailView:View {
    var items:[Item]

    var body : some View{
        List(items){ item in
            HStack{
                Text(item.name)
            }
        }
    }
}

SwiftUI-Text（）调用上的“表达式类型不明确，没有更多上下文”

1 个答案: