PickerView show nothing in text field input - swift

Question

When I tap on the textField, the input area appear, but there's only 1 row, with blank content. (I expect 3 rows: a,b and c)
I changed the returned value in numberOfRowsInComponent and titleForRow functions to constants, but get the same result (1 blank row). Maybe, these 2 functions never be called.
Please help me!
//In ViewDidLoad Function (ViewController.swift):
let myPickerView: MyPickerView = MyPickerView(arrData: ["a","b","c"]){ selected in
print(selected)
}
textField.inputView = myPickerView.picker
//In MyPickerView.swift
class MyPickerView: NSObject, UIPickerViewDelegate, UIPickerViewDataSource {
var arrData: Array<String>
var picker: UIPickerView
var action: (_ selected: String) -> Void
public init(
arrData: Array<String>,
action: #escaping (_ selected: String) -> Void
) {
self.arrData = arrData
self.action = action
self.picker = UIPickerView()
super.init()
self.picker.delegate = self
self.picker.dataSource = self
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return self.arrData.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return self.arrData[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
self.action(self.arrData[row])
}
}

Answer 1

I found the problem. When I changed myPickerView to global variable (put outside of ViewDidLoad), everything fined.
var myPickerView: MyPickerView?
//In ViewDidload
myPickerView = MyPickerView(arrData: ["a","b","c"]){ selected in
print(selected)
}