Когда я запускаю симулятор, у меня появляется вопросительный знак

Question

Мне нужна помощь. Я искал решение в течение двух дней.

class Mam_sEntre_eViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    let notes = [0, 1, 2, 3, 4, 5]

    @IBOutlet weak var noteGoutPickerView: UIPickerView!


    @IBAction func validate() {
        validateNoteMam_sEntre_e()
    }


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

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return notes.count
    }

    private func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> Int? {
        return notes[row]
    }

    private func validateNoteMam_sEntre_e() {
        let noteGoutIndex = noteGoutPickerView.selectedRow(inComponent: 0)
        let noteGout = notes[noteGoutIndex]

    }
}

Answer 1

Изменение

private func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> Int? {
    return notes[row]
}

Для

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

Не личное, возвращаемая строка не Int. Смотри https://developer.apple.com/documentation/uikit/uipickerviewdelegate/1614384-pickerview