SwiftUIでAPI呼び出しでJSONをパース&画像URLから画像を表示（ライブラリ使用）するサンプルコード

ContentView.swift

import SwiftUI
import SDWebImage
import SDWebImageSwiftUI

struct Dog: Codable, Identifiable {
    public var id: String
    public var status: String
    
    enum CodingKeys: String, CodingKey {
        case id = "message"
        case status = "status"
    }
    
    init() {
        self.id = ""
        self.status = ""
    }
}

public class DogFetcher: ObservableObject {
    @Published var dog = Dog()
    
    init() {
        load()
    }
    
    func load() {
        guard let url = URL(string: "https://dog.ceo/api/breeds/image/random") else { return }
        URLSession.shared.dataTask(with: url) { (data, response, error) in
            DispatchQueue.main.async {
                self.dog = try! JSONDecoder().decode(Dog.self, from: data!)
            }
        }.resume()
    }
}

struct ContentView: View {
    @ObservedObject var fetcher = DogFetcher()
    
    var body: some View {
        VStack {
            AnimatedImage(url: URL(string: fetcher.dog.id))
                .resizable()
                .indicator(SDWebImageActivityIndicator.large)
                .scaledToFit()
            Button(action: {
                self.fetcher.load()
            }) {
                Text("Tap!!!")
            }
        }
    }
}

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

事前準備

「File」 > 「Swift Packages」 > 「Add Package Dependency...」で以下URLを入力する
https://github.com/SDWebImage/SDWebImageSwiftUI.git