Pass Json response from one Viewcontroller to another Viewcontroller and populate CollectionView - ios

Question

I'm trying to pass a Json response of an Http request from one controller to another, where in the second one I'd like to create a collection view from the recieved data.
import UIKit
class TableViewController: UITableViewController {
let ingredientList = Ingredients().Ingredients
public var arrayDrinks: Array<Any> = []
let session = URLSession.shared
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.reloadData()
tableView.dataSource = self
tableView.delegate = self
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
// MARK: - number of rows
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.ingredientList.count
}
// MARK: - creating cell
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cellaIng", for: indexPath)
let singoloIngrediente = self.ingredientList[indexPath.row]
cell.textLabel?.text = singoloIngrediente
return cell
}
// MARK: - get the Selected Item
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let selectedItem: String = ingredientList[indexPath.row]
print("The selected ingredient is: \(selectedItem)")
// parameter for http request
let param = String(selectedItem.replacingOccurrences(of: " ", with: "_"))
let url = URL(string: "https://www.thecocktaildb.com/api/json/v1/1/filter.php?i=\(param)")!
// MARK: - Http request
let task = session.dataTask(with: url) { data, response, error in
if error != nil || data == nil {
print("Client error!")
return
}
guard let response = response as? HTTPURLResponse, (200...299).contains(response.statusCode) else {
print("Server error!")
return
}
do {
// data from network request
let decoder = JSONDecoder()
let response = try decoder.decode(ObjectDrink.self, from: data!) // ObjectDrink from Model
self.arrayDrinks.append(response.drinks)
let destinationVC = DrinksListCollectionViewController()
destinationVC.remoteArray = response.drinks
print("print array drink \(destinationVC.remoteArray)")
} catch { print(error) }
}
performSegue(withIdentifier: "InglistSegue", sender: self)
task.resume()
// let destinationVC = DrinksListCollectionViewController()
// destinationVC.remoteArray = self.arrayDrinks
// destinationVC.performSegue(withIdentifier: "InglistSegue", sender: self)
} // END didSelectRowAt
}
When I print the response to the console, the array of the second controller is empty, so no data is passing from the first response (array) to the other controller

Answer 1

You need to present it inside the callback of the URLSession.shared.dataTask like
DispatchQueue.main.async {
self.arrayDrinks.append(response.drinks)
let destinationVC = DrinksListCollectionViewController()
destinationVC.remoteArray = response.drinks
print("print array drink \(destinationVC.remoteArray)")
self.present(destinationVC,animated:true,completion:nil)
}
If it's a segue then replace above with ( also inside the completion )
DispatchQueue.main.async {
performSegue(withIdentifier: "InglistSegue", sender: response.drinks)
}
Add this method
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destinationVC = segue.destination as! DrinksListCollectionViewController
destinationVC.remoteArray = sender as! [Model] // model it type of drinks
}

Answer 2

The view controller that you are moving to is not available yet and your line:
let destinationVC = DrinksListCollectionViewController()
Creates a new view controller which is not the one that your app transitions to. To use the view controller that will be shown, you use prepare(for segue: UIStoryboardSegue, sender: Any?) like so:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destinationVC = segue.destination as? DrinksListCollectionViewController {
destinationVC.remoteArray = self.arrayDrinks
}
}