Swift. Doesn't show data on my screen. iOS and Firebase - ios

Question

I faced such problem. When I launch the ios application, I get a white screen and the data that I take from Firebase is not displayed. How can i fix this problem? I would be grateful for your favorite recommendations for solving my problem
This is my ViewController
class ViewController: UIViewController {
#IBOutlet weak var cv: UICollectionView!
var channel = [Channel]()
override func viewDidLoad() {
super.viewDidLoad()
self.cv.delegate = self
self.cv.dataSource = self
let db = Firestore.firestore()
db.collection("content").getDocuments() {( quarySnapshot, err) in
if let err = err {
print("error")
} else {
for document in quarySnapshot!.documents {
if let name = document.data()["title"] as? Channel {
self.channel.append(name)
}
if let subtitle = document.data()["subtitle"] as? Channel {
self.channel.append(subtitle)
}
}
self.cv.reloadData()
}
}
}
}
extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return channel.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! ContentCell
let channel = channel[indexPath.row]
cell.setup(channel: channel)
return cell
}
}
This is my Model
struct Content {
let contents: [Channel]
}
struct Channel {
let title: String
let subtitle: String
}
This is my Cell
class ContentCell: UICollectionViewCell {
#IBOutlet weak var channelText: UILabel!
#IBOutlet weak var subtitle: UITextView!
func setup(channel: Channel) {
channelText.text = channel.title
subtitle.text = channel.subtitle
}
}

Answer 1

The data retrieved from Firestore can't just magically be cast to your custom type (Channel); it's a simple dictionary. You eighter need to use Codable or do it manually like so:
I can't tell how exactly to convert it as you have not shared the structure of your data in Firestore, but I assume this will work:
db.collection("content").getDocuments() { (snapshot, error) in
if let error = error {
print("error: \(error.localizedDescription)")
} else if let snapshot = snapshot {
for document in snapshot.documents {
let data = document.data()
if let title = data["title"] as? String,
let subtitle = data["subtitle"] as? String {
self.channel.append(Channel(title: title, subtitle: subtitle))
}
}
}
self.cv.reloadData()
}