本文介绍Swift UI中的List 和Alert

效果如下：

import SwiftUI

struct ContentView: View {
    
    //一级导航栏标题
    let listArr = ["first", "second", "third"]
    
    var body: some View {
        NavigationView {
            List(listArr, id: \.self) { title in
                NavigationLink(destination: SecondPage(title: title)) {
                    Text(title)
                }
            }
        }
    }
}

struct SecondPage: View {

    let title: String
    
    //记录选择的哪一行标题,通过它来控制界面显示
    @State private var selectedItemTitle: String = ""
    //控制显示alert view
    @State private var isShowingAlert = false

    var body: some View {
        VStack {
            List(["first", "second", "third"],id: \.self) { title in
                Text(title).onTapGesture(count: 1) {
                    self.selectedItemTitle = title
                    self.isShowingAlert = true
                }
            }
            .alert(isPresented: self.$isShowingAlert) {
                Alert(title: Text(self.selectedItemTitle), message: Text("This is a alert view"), dismissButton: Alert.Button.default(Text("Ok")))
            }
        }
    }
}

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

通过selectedItemTitle来实现界面切换级显示。