swift - Handling asynchronous Firestore data reading in tableView - iOS

Question

I would like to retrieve data from my simple Firestore database

I have this database:

then I have a model class where I have a method responsible for retrieving a data which looks like this:

func getDataFromDatabase() -> [String] {
    var notes: [String] = []
    collectionRef = Firestore.firestore().collection("Notes")

    collectionRef.addSnapshotListener { querySnapshot, error in
            guard let documents = querySnapshot?.documents else {
                print("Error fetching documents: (error!)")
                return
            }
        notes = documents.map { $0["text"]! } as! [String] // text is a field saved in document
            print("inside notes: (notes)")
    }
    print("outside notes: (notes)")
    return notes
}

and as a UI representation I have tableViewController. Let's take one of the methods, for example

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    print("tableview numberOfRowsInSection called")
    return model.getDataFromDatabase().count
}

Then numberOfRows is 0 and the output in the console is:

and I am ending up with no cells in tableView. I added a breakpoint and it doesn't jump inside the listener.

And even though I have 3 of them, they are kinda "late"? They are loaded afterwards. And then the tableView doesn't show anything but console says (later) that there are 3 cells.

If needed, there is also my method for showing the cells names:

 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    print("Cells")
    let cell = tableView.dequeueReusableCell(withIdentifier: "firstCell", for: indexPath)

    cell.textLabel!.text = String(model.getDataFromDatabase()[indexPath.row].prefix(30))

    return cell
}

but this method is not even loaded (no print in the console) and this method is written below the method with numberOfRowsInSection.

I have also 2 errors (I don't know why each line is written twice) and these are:

but I don't think it has something to do with the problem.

Thank you for your help!

Answer 1

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