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iosswiftuiswiftui-navigationlink

how to make the code simpler and more reusable for navigation links with multi dimension dictionary in swiftui?


I have a multi-level dictionary that I need use to build navigation links. Now I have a 2-level depth dictionary:

let multiDimDict: [String: [[String: [String]]]]
= ["A": [["A1": ["A11", "A12"]], ["A2": ["A21", "A22"]]],
   "B": [["B1": ["B11", "B12"]], ["B2": ["B21", "B22"]]]
    ]

I can build the navigation view with all navigation links. However, I feel that I am somehow repeating some code in building navigation links. The question is, if I have a many-level dictionary, say 10-level, I don't think it's wise to build 10 different child-view generators in order to build the complete navigation view. Any idea how to reduce the code?

struct PlayingWithMultiDimNavLink: View {

    let multiDimDict: [String: [[String: [String]]]]
    = ["A": [["A1": ["A11", "A12"]], ["A2": ["A21", "A22"]]],
       "B": [["B1": ["B11", "B12"]], ["B2": ["B21", "B22"]]]
        ]




    var body: some View {

        NavigationView{
            List {
                ForEach(multiDimDict.keys.sorted(), id: \.self) { key in

                    NavigationLink(destination: GenerateChildView(key: key, dict: self.multiDimDict)){

                        Text(key)
                    }

                }
            }
        }

    }
}

This is the :first child view generator:

struct GenerateChildView: View {

    var key: String
    var dict: [String: [[String: [String]]]]
    var infoList: [[String: [String]]]

    init(key: String, dict: [String: [[String: [String]]]]  ){
        self.key = key
        self.dict = dict
        self.infoList = dict[key]!
    }


    var body: some View {
        List{
            ForEach(infoList, id: \.self){ info in
                self.getSomeView(infoList: self.infoList)

            }
        }

}


    func getSomeView(infoList: [[String: [String]]] )-> AnyView{

        let dictToUse = infoList[0]
        return AnyView(
            ForEach(dictToUse.keys.sorted(), id: \.self){ key2 in

                    NavigationLink(destination: GenerateChildView2(infoList: dictToUse[key2]!)){
                        Text(key2)
                    }
                }


        )

    }

The last child-view generator:

struct GenerateChildView2: View {

    var infoList: [String]

    init(infoList: [String]){
        self.infoList = infoList
    }

    var body: some View {

        List{

            ForEach(infoList, id:\.self){ content in

                Text(content)
            }

        }


    }
}

Solution

  • I would start by abandoning the use of a dictionary and use a simple recursive struct that provides a more useful model:

    struct Item: Identifiable {
        let id = UUID()
        var title: String
        var children: [Item] = []
    }
    

    Then you can define a recursive View to display this model:

    struct NavView: View { 
        var item: Item
    
        var body: some View {
            NavigationView {
                List {
                    ForEach(item.children) { child in
                        if child.children.isEmpty {
                            Text(child.title)
                        } else {  
                            NavigationLink(destination: NavView(item:child)) {
                                Text(child.title)
                            }
                        }
                    }
                }.navigationBarTitle(item.title)
            }
        }
    }
    

    Then you can create your hierarchy as required and pass the root to your view:

    let root = Item(title:"",children:
        [Item(title:"A",children:
            [Item(title:"A1", children:
                [Item(title:"A11"),Item(title:"A12")]
                )]),
              Item(title:"B",children:
                [Item(title:"B1"),Item(title:"B2")]
            )]
    )
    
    NavView(item:root))