Value pass from delegate method is nil Swift - ios

Question

I try to send data from one view controller (ItenaryVC) through delegate to another view controller (ItenaryFloatingPanelVC). The VC that initiates ItenaryVC is DiscoverVC. When ItenaryVC load up it will make API calls to get some data, and I want to pass the data received from API calls to the delegate that I created which will pass the data to ItenaryFloatingPanelVC. But the data is not received and it is nil. I also actually using FloatingPanel Library to add the panel in ItenaryVC.
Flow
DiscoverVC -> ItenaryVC + ItenaryFloatingPanelVC (as Flaoting Panel)
DiscoverVC.swift
protocol DiscoverVCDelegate : AnyObject {
func didSendSingleLocationData(_ discoverVC : DiscoverVC , location : Location)
}
class DiscoverVC : UIViewController {
//MARK:- IBOutlets
#IBOutlet weak var collectionView: UICollectionView!
weak var delegate : DiscoverVCDelegate?
private var locationResult = [Location]()
private var selectedAtRow : Int!
//MARK:- Life Cycle
override func viewDidLoad() {
super.viewDidLoad()
renderView()
getLocations()
}
private func renderView() {
collectionView.register(UINib(nibName: R.nib.discoverCell.name, bundle: nil), forCellWithReuseIdentifier: R.reuseIdentifier.discoverCell.identifier)
collectionView.delegate = self
collectionView.dataSource = self
}
private func getLocations(location : String = "locations") {
NetworkManager.shared.getLocations(for: location) { [weak self] location in
switch location {
case .success(let locations):
self?.updateDiscoverUI(with: locations)
case .failure(let error):
print(error.rawValue)
}
}
}
private func updateDiscoverUI(with locations : [Location]) {
DispatchQueue.main.async { [weak self] in
self?.locationResult.append(contentsOf: locations)
self?.collectionView.reloadData()
}
}
}
//MARK:- Delegate
extension DiscoverVC : UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedAtRow = indexPath.row
self.performSegue(withIdentifier: R.segue.discoverVC.goToDetails, sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let destinationVC = segue.destination as? ItenaryVC else { return}
destinationVC.locationDetails = locationResult[selectedAtRow]
destinationVC.imageURL = locationResult[selectedAtRow].image
destinationVC.getItenaries(at: locationResult[selectedAtRow].itenaryName)
delegate?.didSendSingleLocationData(self, location: locationResult[selectedAtRow])
// Remove tab bar when push to other vc
destinationVC.hidesBottomBarWhenPushed = true
}
}
ItenaryVC.swift
import UIKit
import FloatingPanel
protocol ItenaryVCDelegate : AnyObject {
func didSendItenaryData(_ itenaryVC : ItenaryVC, with itenary : [[Days]])
}
class ItenaryVC: UIViewController {
#IBOutlet weak var backgroundImage: UIImageView!
var imageURL : URL!
var locationDetails: Location! {
didSet {
getItenaries(at: locationDetails.itenaryName)
}
}
weak var delegate : ItenaryVCDelegate?
var itenaries = [[Days]]()
//MARK:- Life Cycle
override func viewDidLoad() {
super.viewDidLoad()
setupCard()
setupView()
}
func getItenaries(at itenaries : String = "Melaka"){
NetworkManager.shared.getItenaries(for: itenaries) { [weak self] itenary in
switch itenary {
case .success(let itenary):
// print(itenary)
DispatchQueue.main.async {
self?.itenaries.append(contentsOf: itenary)
self?.delegate?.didSendItenaryData(self! , with: itenary)
}
print(itenaries.count)
case .failure(let error):
print(error.rawValue)
}
}
}
}
//MARK:- Private methods
extension ItenaryVC {
private func setupView() {
backgroundImage.downloaded(from: imageURL)
backgroundImage.contentMode = .scaleAspectFill
}
private func setupCard() {
guard let itenaryFlotingPanelVC = storyboard?.instantiateViewController(identifier: "itenaryPanel") as? ItenaryFloatingPanelVC else { return}
let fpc = FloatingPanelController()
fpc.set(contentViewController: itenaryFlotingPanelVC)
fpc.addPanel(toParent: self)
}
}
ItenaryFloatingPanelVC.swift
import UIKit
class ItenaryFloatingPanelVC: UIViewController{
//MARK:- Outlets
#IBOutlet weak var sloganLabel: UILabel!
#IBOutlet weak var locationLabel: UILabel!
#IBOutlet weak var locDesc: UITextView!
#IBOutlet weak var itenaryTableView: UITableView!
#IBOutlet weak var locDescHC: NSLayoutConstraint!
var itenaries = [[Days]]()
let itenaryVC = ItenaryVC()
let discoverVC = DiscoverVC()
override func viewDidLoad() {
discoverVC.delegate = self
itenaryVC.delegate = self
itenaryTableView.dataSource = self
itenaryTableView.delegate = self
locDescHC.constant = locDesc.contentSize.height
itenaryTableView.register(UINib(nibName: R.nib.itenaryCell.name, bundle: nil), forCellReuseIdentifier: R.nib.itenaryCell.identifier)
}
}
//MARK:- DiscoverVCDelegate
extension ItenaryFloatingPanelVC : DiscoverVCDelegate {
func didSendSingleLocationData(_ discoverVC: DiscoverVC, location: Location) {
print(location)
locationLabel.text = location.locationName
}
}
//MARK:- ItenaryVC Delegate
extension ItenaryFloatingPanelVC : ItenaryVCDelegate {
func didSendItenaryData(_ itenaryVC: ItenaryVC, with itenary: [[Days]]) {
DispatchQueue.main.async {
print(itenary)
self.itenaries.append(contentsOf: itenary)
self.itenaryTableView.reloadData()
print("itenary \(self.itenaries.count)")
}
}
}
Image of ItenaryVC and ItenaryFloatingPanel

Answer 1

Your code doesn't work because you have set the delegate of an newly created ItenaryVC instance:
let itenaryVC = ItenaryVC()
// ...
itenaryVC.delegate = self
itenaryVC here is not the VC that presented self, the ItenaryFloatingPanelVC. It's a brand new one that you created.
Instead of doing that, you can set the delegate in ItenaryVC when you are about to present ItenaryFloatingPanelVC:
private func setupCard() {
guard let itenaryFlotingPanelVC = storyboard?.instantiateViewController(identifier: "itenaryPanel") as? ItenaryFloatingPanelVC else { return }
let fpc = FloatingPanelController()
// here!
self.delegate = itenaryFlotingPanelVC
fpc.set(contentViewController: itenaryFlotingPanelVC)
fpc.addPanel(toParent: self)
}
self is now the ItenaryVC, and itenaryFlotingPanelVC is the VC that self is presenting.

Answer 2

I don't see you call getItenaries() in ItenaryVC. Please check again.