SwiftUI 예시 - id 변경으로 Task가 재실행됨

TaskWithIdView.swift

//
//  TaskWithIdView.swift
//  SwiftUITaskWorkout
//  
//  
//  Created by Paul Hudson.
//  https://twostraws.gumroad.com/l/concurrency

import SwiftUI

struct Message: Decodable, Identifiable {
    let id: Int
    let from: String
    let text: String
}

struct TaskWithIdView: View {
    @State private var messages = [Message]()
    @State private var selectedBox = "Inbox"
    let messageBoxes = ["Inbox", "Sent"]
    
    var body: some View {
        List(messages) { message in
            NavigationLink(destination: {
                Text(message.text)
            }) {
                VStack(alignment: .leading) {
                    Text(message.from).font(.headline)
                    Text(message.text)
                }
            }
        }
        .listStyle(.insetGrouped)
        .navigationTitle(selectedBox)
        .toolbar(content: {
            Picker("Select", selection: $selectedBox) {
                ForEach(messageBoxes, id: \.self, content: Text.init)
                    .pickerStyle(.segmented)
            }
        })
        .onAppear {
            print("onAppear")
        }
        .task(id: selectedBox) {
            print("task start")
            await loadMessages()
        }
    }
    
    
    func loadMessages() async {
        do {
            let url = URL(string: "https://hws.dev/messages.json")!
            let (data, _) = try await URLSession.shared.data(from: url)
            messages = try JSONDecoder().decode([Message].self, from: data)
        } catch {
            messages = [
                Message(id: 0, from: "Failed to load inbox.", text: "Please try again later.")
            ]
        }
    }
}