如何在 SwiftUI 中更改 NavigationView 的目的地？

Question

默認情況下需要 go 到View1 ，當onLongPressGesture到View2時。 @State用於制作它。 代碼如下：

@State var showingView2 = false

if self.showingView2 {
    NavigationLink(destination: View2())
    { Cell(name: View2.name)
        .onLongPressGesture(minimumDuration: 1) {
            self.showingView2 = true
        }
    }

} else {
    NavigationLink(destination: View1())
    { Cell(name: View1.name)
        .onLongPressGesture(minimumDuration: 1) {
            self.showingView2 = true
        }
    }

}

為簡單起見，無法在 UI 中添加新按鈕。 我知道代碼無法運行，但我不知道如何修復它。

任何建議都會幫助我。 謝謝！

==========================================

更新

感謝@Asperi！

但是在我的項目中NavigationView中有ForEach ，在這種情況下答案不起作用。 代碼如下：

import SwiftUI

struct ContentView: View {

    @State private var isLongPressed = false

    let lyrics = ["a", "b", "c"]

    var body: some View {
        NavigationView {
            List() {
                ForEach(0..<lyrics.count) { (index) in
                    NavigationLink(destination:
                        Group {
                            if self.isLongPressed { Destination2() }
                                else { Destination1() }
                        })
                        { Text(self.lyrics[index]) }
                        .simultaneousGesture(LongPressGesture(minimumDuration: 1).onEnded { flag in
                            self.isLongPressed.toggle()
                    })
                }
            }
        }
    }
}

struct Destination1: View {
    var body: some View {
        Text("Destination1")
    }
}

struct Destination2: View {
    var body: some View {
        Text("Destination2")
    }
}

那么在這種情況下如何制作呢？ 而且我不想更改short tap按或long tap按的 function，只需short tap按到View1和long tap按到View2 。 謝謝！

Answer 1

這是一個可能的方法的演示。 使用 Xcode 11.4 / iOS 13.4 測試

struct TestAlternateDestinations: View {
    @State private var isLongPressed = false

    var body: some View {
        NavigationView {
            NavigationLink(destination: Group {
                if isLongPressed { Destination2() }
                    else { Destination1() }}) {
                Text(self.isLongPressed ? "Link2" : "Link1")
            }
            .simultaneousGesture(LongPressGesture(minimumDuration: 1).onEnded { flag in
                self.isLongPressed.toggle()
            })
        }
    }
}

struct Destination1: View {
    var body: some View {
        Text("Destination1")
    }
}

struct Destination2: View {
    var body: some View {
        Text("Destination2")
    }
}

Answer 2

這是基於@Asperi 的最終答案。

而且還有一點小bug。 如果沒有在NavigationLink的名稱中添加很多空格，則長按僅在您點擊“a”“b”“c”時起作用。 在“a”“b”“c”之外的 NavigationLink 的其他空間上，所有的點擊都是短點擊。

import SwiftUI

struct ContentView: View {

    @State private var isLongPressed = false
    @State var currentTag: Int?

    let lyrics = ["a", "b", "c"]

    var body: some View {
        NavigationView {

            List {

                ForEach(0..<lyrics.count) { index in
                    VStack{
                        HStack(alignment: .top) {
                           NavigationLink(destination: Group
                                { if self.isLongPressed { Destination2() } else { Destination1() } }, tag: index, selection: self.$currentTag
                            ) {

// This is still a little bug. If not add many space, the long tap only work when you tap on the "a" "b" "c". On other space of the NavigationLink out of the "a" "b" "c", all tap is short tap.

                                Text(self.lyrics[index] + "                           ")
                            }


                        }
                    }.simultaneousGesture(LongPressGesture().onEnded { _ in
                        print("Got Long Press")
                        self.currentTag = index
                        self.isLongPressed = true
                            })
                    .simultaneousGesture(TapGesture().onEnded{
                        print("Got Tap")
                        self.currentTag = index
                        self.isLongPressed = false
                    })
                    .onAppear(){
                        self.isLongPressed = false
                    }

                }
            }
        }
    }
}


struct Destination1: View {
    var body: some View {
        Text("Destination1")
    }
}

struct Destination2: View {
    var body: some View {
        Text("Destination2")
    }
}