Affichage d'un élément de TodoList depuis le web

SwiftUI-TodoView.swift

import Foundation
import SwiftUI
import Combine

struct Todo: Codable {
    let userId: Int
    let id: Int
    let title: String
    let completed: Bool
}

struct TodoView: View {
    @State var title: String = "Loading..."
    
    var body: some View {
        Text($title.wrappedValue)
            .onReceive(buildPublisher()) { title in
                self.title = title
        }
    }
    
    private func buildPublisher() -> AnyPublisher<String, Never> {
        let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")!

        return URLSession.shared
            .dataTaskPublisher(for: url)
            .tryMap { $0.data }
            .decode(type: Todo.self, decoder: JSONDecoder())
            .compactMap { $0.title }
            .replaceError(with: "Error!")
            .eraseToAnyPublisher()
    }
}

TodoViewController-Combine.swift

import Foundation
import UIKit
import Combine

struct Todo: Codable {
    let userId: Int
    let id: Int
    let title: String
    let completed: Bool
}

class TodoViewController : UIViewController {
    let label = UILabel()
    var cancellable: AnyCancellable?
    
    override func loadView() {
        super.loadView()
        
        let view = UIView()

        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.textAlignment = .center
        label.text = "Loading..."
        
        view.addSubview(label)
        
        label.centerYAnchor
            .constraint(equalTo: view.centerYAnchor)
            .isActive  = true
        label.centerXAnchor
            .constraint(equalTo: view.centerXAnchor)
            .isActive  = true
        label.widthAnchor
            .constraint(lessThanOrEqualTo: view.layoutMarginsGuide.widthAnchor)
            .isActive  = true
        label.heightAnchor
            .constraint(lessThanOrEqualTo: view.layoutMarginsGuide.heightAnchor)
            .isActive  = true
        
        self.view = view
    }
    
    private func loadData() {
        let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")!
        
        cancellable = URLSession.shared
            .dataTaskPublisher(for: url)
            .tryMap { $0.data }
            .decode(type: Todo.self, decoder: JSONDecoder())
            .compactMap { $0.title }
            .replaceError(with: "Error!")
            .receive(on: DispatchQueue.main)
            .assign(to: \.text, on: label)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        loadData()
    }
}

TodoViewController.m

@import Foundation;
@import UIKit;
@import JSONModel;

@interface Todo : JSONModel
    
@property (nonatomic) NSInteger userId;
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *title;
@property (nonatomic) BOOL completed;

@end

@implementation Todo
@end

@interface TodoViewController : UIViewController
    
@property (nonatomic, strong) UILabel *label;

@end

@implementation TodoViewController

- (void)loadView {
    [super loadView];
    
    UIView *view = [[UIView alloc] init];
    UILabel *label = [[UILabel alloc] init];
    
    label.translatesAutoresizingMaskIntoConstraints = NO;
    label.numberOfLines = 0;
    label.textAlignment = NSTextAlignmentCenter;
    label.text = @"Loading...";
    
    [view addSubview:label];
    
    [label.centerYAnchor constraintEqualToAnchor:view.centerYAnchor].active = YES;
    [label.centerXAnchor constraintEqualToAnchor:view.centerXAnchor].active = YES;
    [label.widthAnchor constraintLessThanOrEqualToAnchor:view.layoutMarginsGuide.widthAnchor].active = YES;
    [label.heightAnchor constraintLessThanOrEqualToAnchor:view.layoutMarginsGuide.heightAnchor].active = YES;

    self.label = label;
    self.view = view;
}

- (void)loadData {
    NSURL *url = [NSURL URLWithString:@"https://jsonplaceholder.typicode.com/todos/1"];
    
    [[NSURLSession.sharedSession dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if (data == nil) {
            dispatch_async(dispatch_get_main_queue(), ^{
                self.label.text = @"Error!";
            });
            return;
        }
                
        Todo *todo = [[Todo alloc] initWithData:data error:nil];
        
        if (todo == nil) {
            dispatch_async(dispatch_get_main_queue(), ^{
                self.label.text = @"Error!";
            });
            return;
        }
        
        dispatch_async(dispatch_get_main_queue(), ^{
            self.label.text = todo.title;
        });
    }] resume];
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    
    [self loadData];
}

@end

TodoViewController.swift

import Foundation
import UIKit

struct Todo: Codable {
    let userId: Int
    let id: Int
    let title: String
    let completed: Bool
}

final class TodoViewController: UIViewController {
    let label = UILabel()
    
    override func loadView() {
        super.loadView()
        
        let view = UIView()

        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.textAlignment = .center
        label.text = "Loading..."
        
        view.addSubview(label)
        
        label.centerYAnchor
            .constraint(equalTo: view.centerYAnchor)
            .isActive  = true
        label.centerXAnchor
            .constraint(equalTo: view.centerXAnchor)
            .isActive  = true
        label.widthAnchor
            .constraint(lessThanOrEqualTo: view.layoutMarginsGuide.widthAnchor)
            .isActive  = true
        label.heightAnchor
            .constraint(lessThanOrEqualTo: view.layoutMarginsGuide.heightAnchor)
            .isActive  = true
        
        self.view = view
    }
    
    private func loadData() {
        let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")!
        
        URLSession.shared.dataTask(with: url) { data, response, error in
            guard let data = data else {
                 DispatchQueue.main.async {
                     self.label.text = "Error!"
                 }
                 return
            }
                                               
            guard let todo = try? JSONDecoder().decode(Todo.self, from: data) else {
                DispatchQueue.main.async {
                    self.label.text = "Error!"
                }
                return
            }
            
            DispatchQueue.main.async {
                self.label.text = todo.title
            }
        }.resume()
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        self.loadData()
    }
}