WavigationLinkの送信先を条件付きで変更します

Question

私はリストを持つビューを持っていて、私がクリックしたリストの項目に応じて、私は別のナビゲーションリンクを開く必要があります。

私はRow Modelリストの1行のために（私は実際には常にコレクションと呼ばれるカスタムメイドの要素を使用していますが、hstackと呼ばれるカスタムメイドの要素を使用しています。 icollectionView）

行モデルビューでは、私は1つの宛先のみを指定してくださいナビゲーションリンクの場合だけです。

私が考えることができる解決策は、クリックされたリストのアイテムのインデックスを取得し、それに基づいて特定のビューを開くことです。しかし、私はそれを仕事にすることができませんでした。

私は基本的にリスト内の各要素が異なるビューを開く必要があります。

どんな助けにかかっています！ ありがとうございました！：）

---

GroupDetail.Swift.

import SwiftUI

// data displayed in the collection view
var itemsGroupData = [
  ItemsGroupModel("Projects"), // should open ProjectsView()
  ItemsGroupModel("People"), //should open PeopleView()
  ItemsGroupModel("Agenda"), //should open AgendaView()
  ItemsGroupModel("Name") //should open NameView()
]

// main view where the collection view is shown
struct GroupDetail: View {

  var body: some View {

    // FAMOUS COLLECTION ELEMENT
    Collection(itemsGroupData, columns: 2, scrollIndicators: false) { index in
      ItemsGroupRow(data: index)
    }
  }
}

// model of the data
struct ItemsGroupModel: Identifiable {
  var id: UUID
  let title: String

  init(_ title: String) {
    self.id = UUID()
    self.title = title
  }
}

// row type of the collection view
struct ItemsGroupRow: View {

  var body: some View {

    // This model is for one row
    // I need to specify what view to open depending on what item of the collection view was selected (clicked on)
    NavigationLink(destination: ProjectsView()) { // open ProjectsView only if the user clicked on the item "Projects" of the list etc..
      Text(data.title)
    }
  }
}

-----------------------------------------------------------------------

Collection.Swift

// this custom struct creates the UIKit equivalent of the UICollectionView
// it uses a HStack and a VStack to make columns and rows

import SwiftUI

@available(iOS 13.0, OSX 10.15, *)
public struct Collection<Data, Content>: View
where Data: RandomAccessCollection, Content: View, Data.Element: Identifiable {

  private struct CollectionIndex: Identifiable { var id: Int }

  // MARK: - STORED PROPERTIES
  private let columns: Int
  private let columnsInLandscape: Int
  private let vSpacing: CGFloat
  private let hSpacing: CGFloat
  private let vPadding: CGFloat
  private let hPadding: CGFloat
  private let scrollIndicators: Bool
  private let axisSet: Axis.Set

  private let data: [Data.Element]
  private let content: (Data.Element) -> Content

  // MARK: - COMPUTED PROPERTIES
  private var actualRows: Int {
    return data.count / self.actualColumns
  }

  private var actualColumns: Int {
    return UIDevice.current.orientation.isLandscape ? columnsInLandscape : columns
  }

  // MARK: - INIT
  public init(_ data: Data,
              columns: Int = 2,
              columnsInLandscape: Int? = nil,
              scrollIndicators: Bool = true,
              axisSet: Axis.Set = .vertical,
              vSpacing: CGFloat = 10,
              hSpacing: CGFloat = 10,
              vPadding: CGFloat = 10,
              hPadding: CGFloat = 10,
              content: @escaping (Data.Element) -> Content) {
    self.data = data.map { $0 }
    self.content = content
    self.columns = max(1, columns)
    self.columnsInLandscape = columnsInLandscape ?? max(1, columns)
    self.vSpacing = vSpacing
    self.hSpacing = hSpacing
    self.vPadding = vPadding
    self.hPadding = hPadding
    self.scrollIndicators = scrollIndicators
    self.axisSet = axisSet
  }

  // MARK: - BODY
  public var body : some View {

    GeometryReader { geometry in
      ScrollView(self.axisSet, showsIndicators: self.scrollIndicators) {
        if self.axisSet == .horizontal {
          HStack(alignment: .center, spacing: self.hSpacing) {
            ForEach((0 ..< self.actualRows).map { CollectionIndex(id: $0) }) { row in
              self.createRow(row.id, geometry: geometry)
            }
          }
        } else {
          VStack(spacing: self.vSpacing) {
            ForEach((0 ..< self.actualRows).map { CollectionIndex(id: $0) }) { row in
              self.createRow(row.id * self.actualColumns, geometry: geometry)
            }
            // LAST ROW HANDLING
            if (self.data.count % self.actualColumns > 0) {
              self.createRow(self.actualRows * self.actualColumns, geometry: geometry, isLastRow: true)
                .padding(.bottom, self.vPadding)
            }
          }
        }
      }
    }
  }

  // MARK: - HELPER FUNCTIONS
  private func createRow(_ index: Int, geometry: GeometryProxy, isLastRow: Bool = false) -> some View {
    HStack(spacing: self.hSpacing) {
      ForEach((0 ..< actualColumns).map { CollectionIndex(id: $0) }) { column in
        self.contentAtIndex(index + column.id)
          .frame(width: self.contentWidthForGeometry(geometry))
          .opacity(!isLastRow || column.id < self.data.count % self.actualColumns ? 1.0 : 0.0)
      }
    }
  }

  private func contentAtIndex(_ index: Int) -> Content {
    // (Addressing the workaround with transparent content in the last row) :
    let object = index < data.count ? data[index] : data[data.count - 1]
    return content(object)
  }

  private func contentWidthForGeometry(_ geometry: GeometryProxy) -> CGFloat {
    let hSpacings = hSpacing * (CGFloat(self.actualColumns) - 1)
    let width = geometry.size.width - hSpacings - hPadding * 2
    return width / CGFloat(self.actualColumns)
  }
}
 _

Answer 1

私はあなたが要素を見たいと思って、どのビューを表示するかを決定したいと思います。列挙型を使用することもできます。

Collection要素を渡すので、それを使用して条件付きを使用できます。

struct ProjectView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("Project title = \(row.title)")
    }
}

struct NonProjectView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("Non-Project title = \(row.title)")
    }
}

// row type of the collection view
struct ItemsGroupRow: View {

    var data: ItemsGroupModel

    var body: some View {

        // This model is for one row
        // I need to specify what view to open depending on what item of the collection view was selected (clicked on)
        NavigationLink(destination: {
            VStack{
                if data.title.contains("project") {
                    ProjectView(row: data)
                } else {
                    NonProjectView(row: data)
                }
            }
        }()) { // open ProjectsView only if the user clicked on the item "Projects" of the list etc..
            Text(data.title)
        }
    }
}
 _

注：コレクションにいくつかのバグがあると思います。

enumを使用した例正しく機能しない：

import SwiftUI

struct ConditionalNavigationLinkView: View {
    var body: some View {
        GroupDetail()
    }
}

// data displayed in the collection view
var itemsGroupData = [
    ItemsGroupModel(.project), // should open ProjectsView()
    ItemsGroupModel(.people), //should open PeopleView()
    ItemsGroupModel(.agenda), //should open AgendaView()
    ItemsGroupModel(.name) //should open NameView()
]

// main view where the collection view is shown
struct GroupDetail: View {

    var body: some View {

        NavigationView{
            // FAMOUS COLLECTION ELEMENT
            Collection(itemsGroupData, columns: 2, scrollIndicators: false) { row in
                ItemsGroupRow(data: row)
            }
        }
    }
}

enum ItemsGroupModelType: String {
    case project = "Projects"
    case people = "People"
    case agenda = "Agenda"
    case name = "Name"
}

// model of the data
struct ItemsGroupModel: Identifiable {
    var id: UUID
    let type: ItemsGroupModelType

    init(_ type: ItemsGroupModelType) {
        self.id = UUID()
        self.type = type
    }
}

struct ProjectView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("Projects \(row.type.rawValue)")
    }
}

struct NameView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("NameView \(row.type.rawValue)")
    }
}

struct PeopleView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("PeopleView \(row.type.rawValue)")
    }
}

struct AgendaView: View {
    var row: ItemsGroupModel
    var body: some View {
        Text("AgendaView \(row.type.rawValue)")
    }
}

// row type of the collection view
struct ItemsGroupRow: View {

    func printingEmptyView() -> EmptyView {
        print("type: \(data.type.rawValue)")
        return EmptyView()
    }

    var data: ItemsGroupModel

    var body: some View {

        // This model is for one row
        // I need to specify what view to open depending on what item of the collection view was selected (clicked on)
        NavigationLink(destination: {
            //print("Hello")

            VStack{
                self.printingEmptyView()
                if data.type == .project {
                    ProjectView(row: data)
                }
                if data.type == .people {
                    PeopleView(row: data)
                }
                if data.type == .agenda {
                    AgendaView(row: data)
                }
                if data.type == .name {
                    NameView(row: data)
                }
            }
        }()) { // open ProjectsView only if the user clicked on the item "Projects" of the list etc..
            Text(data.type.rawValue)
        }
    }
}
 _