SwifUI中的生命周期:在离开NavigationView层次结构的子视图时运行代码

import SwiftUI

struct ContentView: View {
    var body: some View {
        NavigationView {
            NavigationLink(destination: SecondView()) {
                Text("Go to Second View")
            }
            .navigationBarTitle("First View")
        }
    }
}

struct SecondView: View {
    @State private var data: String = ""
    
    var body: some View {
        VStack {
            TextField("Enter data", text: $data)
                .textFieldStyle(RoundedBorderTextFieldStyle())
            
            Button(action: {
                // 处理按钮点击事件
            }) {
                Text("Submit")
            }
        }
        .onAppear {
            print("SecondView appeared")
            // 执行进入视图时的操作
        }
        .onDisappear {
            print("SecondView disappeared")
            // 执行离开视图时的操作
            saveData()
        }
    }
    
    func saveData() {
        // 保存数据的逻辑
        print("Data saved: \(data)")
    }
}

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