如何從父級運行子函式？

我想通過按下父視圖中的按鈕來呼叫 childFunction() 演示 ChildView。

import SwiftUI

struct ChildView: View {
    
    func childFunction() {
        print("I am the child")
    }

    var body: some View {
      Text("I am the child")
    }
}

struct ContentView: View {
    var function: (() -> Void)?

    var body: some View {
        ChildView()
        
        Button(action: {
            self.function!()
        }, label: {
            Text("Button")
        })
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

更新：謝謝@RajaKishan，它可以作業，但我也需要它遞回地作業

import SwiftUI

struct ContentView: View {
    @State var text: String = "Parent"
    var isNavigationViewAvailable = true
    
    func function() {
        print("This view is \(text)")
    }
    
    var body: some View {
        
        VStack {
            if isNavigationViewAvailable  {
                Button(action: {
                    function()
                }, label: {
                    Text("Button")
                })
            }
           
            
            if isNavigationViewAvailable {
                NavigationView {
                    List {
                        NavigationLink("Child1") {
                            ContentView(text: "Child1", isNavigationViewAvailable: false)
                        }
                        NavigationLink("Child2") {
                            ContentView(text: "Child2", isNavigationViewAvailable: false)
                        }
                        NavigationLink("Child3") {
                            ContentView(text: "Child3", isNavigationViewAvailable: false)
                        }
                    }
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

也許不是最好看的例子，但問題是，如何在用戶訪問相應的孩子后強制按鈕運行它的孩子的功能。

就像，當用戶按下按鈕時，它會列印“這個視圖是父視圖”。用戶來到 child1 后，按下按鈕應該列印“這個視圖是 Child1”等等。因此，按鈕運行的函式應該從最后一個子節點參考。

uj5u.com熱心網友回復：

您可以為 ChildView 創建一個物件。

struct ChildView: View {
 
    func childFunction() {
        print("I am the child")
    }
    
    var body: some View {
        Text("I am the child")
    }
}

struct ContentView: View {
    
    let childView = ChildView()
    
    var body: some View {
        childView
        Button(action: {
            childView.childFunction()
        }, label: {
            Text("Button")
        })
    }
}

編輯：對于串列，您可以使用模型的陣列并按索引呼叫目標函式。

這是一個簡單的子父示例。

struct ChildView: View {
    var text: String
    
    func childFunction() {
        print("This view is \(text)")
    }
    
    var body: some View {
        Text("I am the child")
    }
}



struct ContentView55: View {
    
    @State private var arrData = [Model(title: "Child1", destination: ChildView(text: "Child1")),
                                           Model(title: "Child2", destination: ChildView(text: "Child2")),
                                           Model(title: "Child3", destination: ChildView(text: "Child3"))]
    
    var body: some View {
        
        VStack {
            Button(action: {
                arrData[1].destination.childFunction()
            }, label: {
                Text("Button")
            })
            
            NavigationView {
                SwiftUI.List(arrData) {
                    NavigationLink($0.title, destination: $0.destination)
                }
            }
        }
    }
    
}
struct Model: Identifiable {
    var id = UUID()
    var title: String
    var destination: ChildView
}

注意：您需要為行建立索引才能呼叫子函式。

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