CODEWITHSUNDEEP
swiftgoogle-cloud-firestore
alexandrov
alexandrov

Reputation: 441

Array isn't updating in Swift

When you start the application, you should get a line from the Firestore documents and write to an array, (array)

    var items = [String]()

override func viewDidLoad() {
        let db = Firestore.firestore()
        db.collection("cities").getDocuments() { (querySnapshot, err) in
            if let err = err {
                print("Error getting documents: \(err)")
            } else {
                for document in querySnapshot!.documents {
                    print("\(document.documentID) => \(document.data())")
                    self.items.append(document.data()["title"] as! String)
                }
            }
        }

    }

then in the cell creation function, the text should be changed to a line from the array.

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! colCell
        print(self.items)
        cell.myLabel.text = self.items[indexPath.item]

        return cell
    }

But the array with strings from the firestore is not updated in the cell creation function. Why?

(I printed out array in viewDidLoad and in cell, it's updated in viewDidLoad and not updated in cell)

Upvotes: 0

Views: 70

Answers (2)

Ani
Ani

Reputation: 1

You can reload the given cell after updating the date like this,

collectionView.reloadItemsAtIndexPaths(arrayOfIndexPaths)

it is optimised way to update UICollectionView.

Upvotes: 0

Shehata Gamal
Shehata Gamal

Reputation: 100503

You need to reload the collectionView as the call to firestore is asynchronous 

for document in querySnapshot!.documents {
   print("\(document.documentID) => \(document.data())")
   self.items.append(document.data()["title"] as! String)
}
self.collectionView.reloadData()

Upvotes: 2

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