SwiftUI News API App - Load More Data List View Infinite Scroll

SwiftUI News API App - Load More Data List View Infinite Scroll

News API : https://newsapi.org/

ContentView.swift

 
//
//  ContentView.swift
//  SwiftUIProject
//
//  Created by Cairocoders
//

import SwiftUI

struct ContentView: View {

    var body: some View {
        NewsFeedView()
    }
}

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

struct NewsFeedView: View {
    @ObservedObject var newsFeed = NewsFeed()
    
    var body: some View {
        NavigationView {
            List(newsFeed) { (article: NewsListItem) in
                NavigationLink(destination: NewsListItemView(article: article)) {
                    NewsListItemListView(article: article)
                        .onAppear {
                            self.newsFeed.loadMoreArticles(currentItem: article)
                    }
                }
            }
        .navigationBarTitle("Apple News")
        }
    }
}

struct NewsListItemView: View {
    var article: NewsListItem
    
    var body: some View {
        VStack {
            UrlWebView(urlToDisplay: URL(string: article.url)!)
                .edgesIgnoringSafeArea(.all)
                .navigationBarTitle(article.title)
        }
    }
}

struct NewsListItemListView: View {
    var article: NewsListItem
    
    var body: some View {
        HStack {
            VStack(alignment: .leading) {
                Text("\(article.title)")
                    .font(.headline)
                Text("\(article.author ?? "No Author")")
                    .font(.subheadline)
            }
        }
    }
}

NewsFeedModels.swift

 
//
//  NewsFeedModels.swift
//  SwiftUIProject
//
//  Created by Cairocoders
//

import Foundation

class NewsFeed: ObservableObject, RandomAccessCollection {
    typealias Element = NewsListItem
    
    @Published var newsListItems = [NewsListItem]()
    
    var startIndex: Int { newsListItems.startIndex }
    var endIndex: Int { newsListItems.endIndex }
    var loadStatus = LoadStatus.ready(nextPage: 1)
    
    var urlBase = "https://newsapi.org/v2/everything?q=apple&sortBy=popularity&apiKey=55c250f06e1144c29a3ec4d2530adbe5&language=en&page="
 
    init() {
        loadMoreArticles()
    }
    
    subscript(position: Int) -> NewsListItem {
        return newsListItems[position]
    }
    
    func loadMoreArticles(currentItem: NewsListItem? = nil) {
        
        if !shouldLoadMoreData(currentItem: currentItem) {
            return
        }
        guard case let .ready(page) = loadStatus else {
            return
        }
        loadStatus = .loading(page: page)
        let urlString = "\(urlBase)\(page)"
        
        let url = URL(string: urlString)!
        let task = URLSession.shared.dataTask(with: url, completionHandler: parseArticlesFromResponse(data:response:error:))
        task.resume()
    }
    
    func shouldLoadMoreData(currentItem: NewsListItem? = nil) -> Bool {
        guard let currentItem = currentItem else {
            return true
        }
        
        for n in (newsListItems.count - 4)...(newsListItems.count-1) {
            if n >= 0 && currentItem.uuid == newsListItems[n].uuid {
                return true
            }
        }
        return false
    }
    
    func parseArticlesFromResponse(data: Data?, response: URLResponse?, error: Error?) {
        guard error == nil else {
            print("Error: \(error!)")
            loadStatus = .parseError
            return
        }
        guard let data = data else {
            print("No data found")
            loadStatus = .parseError
            return
        }
        
        let newArticles = parseArticlesFromData(data: data)
        DispatchQueue.main.async {
            self.newsListItems.append(contentsOf: newArticles)
            if newArticles.count == 0 {
                self.loadStatus = .done
            } else {
                guard case let .loading(page) = self.loadStatus else {
                    fatalError("loadSatus is in a bad state")
                }
                self.loadStatus = .ready(nextPage: page + 1)
            }
        }
    }
    
    func parseArticlesFromData(data: Data) -> [NewsListItem] {
        var response: NewsApiResponse
        do {
            response = try JSONDecoder().decode(NewsApiResponse.self, from: data)
        } catch {
            print("Error parsing the JSON: \(error)")
            return []
        }
        
        if response.status != "ok" {
            print("Status is not ok: \(response.status)")
            return []
        }
        
        return response.articles ?? []
    }
    
    enum LoadStatus {
        case ready (nextPage: Int)
        case loading (page: Int)
        case parseError
        case done
    }
}

class NewsApiResponse: Codable {
    var status: String
    var articles: [NewsListItem]?
}

class NewsListItem: Identifiable, Codable {
    var uuid = UUID()
    
    var author: String?
    var title: String
    var url: String
    
    enum CodingKeys: String, CodingKey {
        case author, title, url
    }
}

UrlWebView.swift

 
//
//  UrlWebView.swift
//  SwiftUIProject
//
//  Created by Cairocoders
//

import SwiftUI
import WebKit

struct UrlWebView: UIViewRepresentable {
    typealias UIViewType = WKWebView
    
    var urlToDisplay: URL
    
    func makeUIView(context: Context) -> WKWebView {
        let webView = WKWebView()
        
        webView.load(URLRequest(url: urlToDisplay))
        
        return webView
    }
    
    func updateUIView(_ uiView: WKWebView, context: Context) {
        
    }
}