UIPickerView and subclass Array in Swift 3

Question

I am new on Swift and Firebase, but I am building an app that uses in one view controller a picker view and the data to populate it comes from an Firebase structure that put data into an array with parameters stored in a subclass.

I can see all the data printed in the debugger console, (Firebase is OK running here) showing me that the array received data from Firebase (and I can insert new items using a method for this with a button in this new controller too), but it looks that the methods for pickerview (numberOfCOmponents, numberOfRowsInComponent and titleforRow) initialize before the viewDidLoad, where the method who brings the data from Firebase to the array occur, and I have a count = 0.

My pickerview stays empty. I have no crash. At the debugger console, I can see the printed count = 0 and then, with a print placed at the end of viewDidLoad method, it counts how many registers I actually have and show them.

I want to know what should I do for the array be fulfilled with Firebase data before pickeview methods do it, and these data como to the pickerview rows. Thank you.

var refw2: [PickerArrayClasses] = []
@IBOutlet weak var pckProfessores: UIPickerView!

override func viewDidLoad() {
    super.viewDidLoad()

    let refW = FIRDatabase.database().reference().child("avaliacao").child("equipe")
    refW.queryOrdered(byChild: "nomePreceptor").observe(.value, with: {(snapshot) in

        var newTeste2: [PickerArrayClasses] = []
        for resposta in snapshot.children {
            let itemsAadicionar = PickerArrayClasses(snapshot: resposta as! FIRDataSnapshot)
            newTeste2.append(itemsAadicionar)
        }
        self.refw2 = newTeste2
        print("ITENS NO ARRAY RefW2 \(newTeste2)")
    })

    self.pckProfessores.delegate = self
    self.pckProfessores.dataSource = self
    self.pckAvaliador.delegate = self
    self.pckAvaliador.dataSource = self

}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        print("CONTAR ITENS NO REFW2 - SECAO COUNT = \(refw2.count)")
        return refw2.count
 }

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
   return refw2[row].nomePrecep
 }

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    let PreceptorEscolhido = refw2[row].nomePrecep
     print("PRECEPTOR ESCOLHIDO: \(PreceptorEscolhido)")
}

Information at the Debugger Console

CONTAR ITENS NO REFW2 - SECAO COUNT = 0
ITENS NO ARRAY RefW2 
[ChkList.PickerArrayClasses(nomePrecep: Optional("2222222222"), key: -KYiOkUH1cFXj7q7LkTi),
ChkList.PickerArrayClasses(nomePrecep: Optional("33333"), key: -KYiOvOjfxZpuUkxM4bn),
ChkList.PickerArrayClasses(nomePrecep: Optional("5555555555555555555"), key: -KYiPsHTumA0qdTKkbMT),
ChkList.PickerArrayClasses(nomePrecep: Optional("77777"), key: -KYikQ5dveM3L7JielTt), 
ChkList.PickerArrayClasses(nomePrecep: Optional("MARK BONINHA"), key: -KYi7XofWn9Um6FVV3M6), 
ChkList.PickerArrayClasses(nomePrecep: Optional("OUTRO MARK"), key: -KYi7t6OEllWTmMl655T), 
ChkList.PickerArrayClasses(nomePrecep: Optional("dfddf"), key: -KYiI8sTLE6G3olzOtAJ)]

Answer 1

I could solve this issue adding the following line into viewDidLoad method:

self.pckProfessores.reloadAllComponents()

just after self.refw2 = newTeste2 line.