Load data again after segue is done - ios

Question

I would like to know how should I behave if I got several articles in table view controller, which are loaded and parsed from some API. Then I would like to click on some article to view his detail.
Should I load all articles on start up with all data and then pass concrete whole article to next detail table controller or just send article id and in new table controller load again whole one article with passed id?
I think that is much better second method, but have no idea how to do it. Any help? Thanks a lot.
EDIT: added code
MainTableViewController:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let articleId = articles[indexPath.row].Id
let destination = DetailTableViewController()
destination.articleId = articleId
destination.performSegue(withIdentifier: "Main", sender: self)
}
DetailTableViewController:
override func viewDidLoad() {
super.viewDidLoad()
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 140
// Vyzkoušíme jestli jsme připojeni do internetu
if Helper.hasConnectivity() {
// Zapneme načítací obrazovku
setLoadingScreen()
// Načteme jídla
loadMainArticles()
} else {
promptAlert(title: "Upozornění", message: "Ujistěte se, že Vaše zařízení je připojené k internetu")
}
}
private func loadMainArticles() {
ApiService.sharedInstance.fetchArticle(part: "GetArticle", articleId: "brananske-posviceni--spravna-lidova-zabava-s-pecenou-husou") { (articles: [Article]) in
self.removeLoadingScreen()
self.tableView.separatorStyle = .singleLine
if articles.count == 0 {
self.promptAlert(title: "Upozornění", message: "Žádná data")
}
self.selectedArticle = articles[0]
self.tableView.reloadData()
}
}
ApiService:
func fetchArticle(part: String, articleId: String, completion: #escaping ([Article]) -> ()) {
var Id = ""
var Title = ""
var Content = ""
var Picture = ""
var PublishDate = ""
let url = NSURL(string: "http://xxx")
URLSession.shared.dataTask(with: url! as URL) { (data, response, error) in
if error != nil {
print(error as Any)
return
}
do {
let json = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments)
var articles = [Article]()
for dictionary in json as! [[String: AnyObject]] {
.
.
.
let article = Article(Id: Id, Title: Title, Content: Content, Picture: Picture, PublishDate: PublishDate, Categories: Categories)
articles.append(article!)
}
DispatchQueue.main.async(execute: {
completion(articles)
})
}
}.resume()
}
The problem is that when I do the segue after click on row, then should loadMainArticles. The method is triggered, but always stops on URLSession row and immediately jump to resume() and the completion block is never triggered. Is there any reason why?

Answer 1

This is a choice that should be done according to article data model size.
You should pay attention to which data you need to show on TableView single cell and which on Article detail page.
I suppose you to show:
Title and posted hour in TableView
Title, hour, long description, maybe some image in Detail page
In this case i would reccommend you to download only title and hour for each article item, and then, in detail page, download single item details (avoid to download unused content, since user could not open every item).
Otherwise, if amounts of data are similar, download all informations on first connection and open detail page without making any other network request.
I think that is much better second method, but have no idea how to do it.
You need to retrieve article id from TableView selected cell and pass it to DetailPageViewController using prepareForSegue. In DetailPageViewController ViewDidLoad send article id to your backend api and retrieve article details to show.