Problem with saving data using Core Data in swift - ios

Question

I'm trying to save data to the core data and then display it on another view controller. I have a table view with custom cell, which have a button. I've created a selector, so when we tap on the button in each of the cell, it should save all the data from the cell. Here is my parent view controller:
import UIKit
import SafariServices
import CoreData
class ViewController: UIViewController, UISearchBarDelegate {
#IBOutlet weak var pecodeTableView: UITableView!
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var savedNews = [SavedNews]()
var newsTitle: String?
var newsAuthor: String?
var urlString: String?
var newsDate: String?
var isSaved: Bool = false
private var articles = [Article]()
private var viewModels = [NewsTableViewCellViewModel]()
private let searchVC = UISearchController(searchResultsController: nil)
override func viewDidLoad() {
super.viewDidLoad()
pecodeTableView.delegate = self
pecodeTableView.dataSource = self
pecodeTableView.register(UINib(nibName: S.CustomCell.customNewsCell, bundle: nil), forCellReuseIdentifier: S.CustomCell.customCellIdentifier)
fetchAllNews()
createSearchBar()
loadNews()
saveNews()
countNewsToCategory()
}
#IBAction func goToFavouritesNews(_ sender: UIButton) {
performSegue(withIdentifier: S.Segues.goToFav, sender: self)
}
private func fetchAllNews() {
APICaller.shared.getAllStories { [weak self] result in
switch result {
case .success(let articles):
self?.articles = articles
self?.viewModels = articles.compactMap({
NewsTableViewCellViewModel(author: $0.author ?? "Unknown", title: $0.title, subtitle: $0.description ?? "No description", imageURL: URL(string: $0.urlToImage ?? "")
)
})
DispatchQueue.main.async {
self?.pecodeTableView.reloadData()
}
case .failure(let error):
print(error)
}
}
}
private func createSearchBar() {
navigationItem.searchController = searchVC
searchVC.searchBar.delegate = self
}
}
extension ViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 120
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return viewModels.count
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: S.CustomCell.customCellIdentifier, for: indexPath) as! CustomNewsCell
cell.configure(with: viewModels[indexPath.row])
cell.saveNewsBtn.tag = indexPath.row
cell.saveNewsBtn.addTarget(self, action: #selector(didTapCellButton(sender:)), for: .touchUpInside)
return cell
}
#objc func didTapCellButton(sender: UIButton) {
guard viewModels.indices.contains(sender.tag) else { return }
print("Done")// check element exist in tableview datasource
if !isSaved {
saveNews()
print("success")
}
//Configure selected button or update model
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
let article = articles[indexPath.row]
guard let url = URL(string: article.url ?? "") else {
return
}
let vc = SFSafariViewController(url: url)
present(vc, animated: true)
}
//Search
func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
guard let text = searchBar.text, !text.isEmpty else {
return
}
APICaller.shared.Search(with: text) { [weak self] result in
switch result {
case .success(let articles):
self?.articles = articles
self?.viewModels = articles.compactMap({
NewsTableViewCellViewModel(author: $0.author ?? "Unknown", title: $0.title, subtitle: $0.description ?? "No description", imageURL: URL(string: $0.urlToImage ?? "")
)
})
DispatchQueue.main.async {
self?.pecodeTableView.reloadData()
self?.searchVC.dismiss(animated: true, completion: nil)
}
case .failure(let error):
print(error)
}
}
}
}
extension ViewController {
func loadNews() {
let request: NSFetchRequest<SavedNews> = SavedNews.fetchRequest()
do {
let savedNews = try context.fetch(request)
//Handle saved news
if savedNews.count > 0 {
isSaved = true
}
} catch {
print("Error fetching data from context \(error)")
}
}
func saveNews() {
//Initialize the context
let news = SavedNews(context: self.context)
//Putting data
news.title = newsTitle
news.author = newsAuthor
news.publishedAt = newsDate
news.url = urlString
do {
try context.save()
} catch {
print("Error when saving data \(error)")
}
}
func countNewsToCategory() {
//Initialize the context
let request: NSFetchRequest<SavedNews> = SavedNews.fetchRequest()
let predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [
])
request.predicate = predicate
do {
savedNews = try context.fetch(request)
} catch {
print("Error fetching data from category \(error)")
}
}
}
I don't know where is the problem, I've created a correct data model, but data could not be saved. Here is my model:
import Foundation
struct APIResponse: Codable {
let articles: [Article]
}
struct Article: Codable {
let author: String?
let source: Source
let title: String
let description: String?
let url: String?
let urlToImage: String?
let publishedAt: String
}
struct Source: Codable {
let name: String
}
And also my model in Core Data:
My second view controller, to which I want display the data:
import UIKit
import CoreData
class FavouriteNewsViewController: UIViewController {
#IBOutlet weak var favTableView: UITableView!
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var savedNews = [SavedNews]()
override func viewDidLoad() {
super.viewDidLoad()
favTableView.delegate = self
favTableView.delegate = self
loadSavedNews()
favTableView.register(UINib(nibName: S.FavouriteCell.favouriteCell, bundle: nil), forCellReuseIdentifier: S.FavouriteCell.favouriteCellIdentifier)
// Do any additional setup after loading the view.
}
}
extension FavouriteNewsViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return savedNews.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = favTableView.dequeueReusableCell(withIdentifier: S.FavouriteCell.favouriteCellIdentifier, for: indexPath) as! FavouritesCell
print(savedNews)
let article = savedNews[indexPath.row]
if let articleTitle = article.title {
cell.favTitle.text = articleTitle
}
if let articleAuthor = article.author {
cell.favAuthor.text = articleAuthor
}
if let articleDesc = article.desc {
cell.favDesc.text = article.desc
}
return cell
}
}
extension FavouriteNewsViewController {
func loadSavedNews() {
let request: NSFetchRequest<SavedNews> = SavedNews.fetchRequest()
do {
savedNews = try context.fetch(request)
} catch {
print("Error fetching data from context \(error)")
}
}
func deleteNews(at indexPath: IndexPath) {
// Delete From NSObject
context.delete(savedNews[indexPath.row])
// Delete From current News list
savedNews.remove(at: indexPath.row)
// Save deletion
do {
try context.save()
} catch {
print("Error when saving data \(error)")
}
}
}

Answer 1

you did not assign your properties that you are trying to save
newsTitle,newsAuthor,newsDate,urlString
seems these properties have nil value . make sure these properties have valid value before save .