add UIPickerView as subview, very weired - ios

Question

recently I need a solution to show a present-like pickerView for choosing data for some property, like profile.
what I did is
1, create a empty project
2, create a AViewController which will be used as subview. And I add a pickerView and a navigation bar into that view and adjust the view's height to around 260.
3, write code in that AViewController's class.
class APickerViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
#IBOutlet weak var pickerView:UIPickerView!
let dataList = [["a","b","c","d"]]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
//pickerView.dataSource = self
//pickerView.delegate = self
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return dataList.count
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return dataList[component].count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return dataList[component][row]
}
4, write code in Main ViewController to add the AViewController's View as subview.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let pickerViewController = storyboard?.instantiateViewController(withIdentifier: String(APickerViewController.self)) as! APickerViewController
self.view.addSubview(pickerViewController.view)
self.view.bringSubview(toFront: pickerViewController.view)
pickerViewController.view.frame = CGRect(x: 0, y: self.view.frame.height - 300, width: self.view.frame.width, height: 300)
}
and also one question here actually I'm not that sure the difference.
A:
let pickerViewController = storyboard?.instantiateViewController(withIdentifier: String(APickerViewController.self)) as! APickerViewController
B:
let pickerViewController = APickerViewController()
What's the different of A and B ? If I do some #IBOutlet settings by Interface Builder will be affected or what ?
5, go and ... get weired ...
the function
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return dataList[component].count
}
sometime's get called many times and sometimes not get called.
and the data was not show in pickerView and sometimes only show row 1,2 and no others and if I flick up or down those 1,2 row data disappeared.
if anyone have a better solution of using pickerView as option popup window ?
Help.
Thanks

Answer 1

class EditViewController: UIViewController,UITextFieldDelegate,UIPickerViewDelegate{
var picker : UIPickerView = UIPickerView()
var toolBar : UIToolbar = UIToolbar()
#IBOutlet var txtFieldState: UITextField!
var stateArray = ["Andaman & Nicobar Island","Andhra Pradesh","Arunachal Pradesh","Assam","Bihar","Chandigarh","Chhattisgarh","Dadra & Nagar"]
override func viewDidLoad() {
super.viewDidLoad()
txtFieldState.delegate = self
}
func textFieldDidBeginEditing(textField: UITextField) {
if textField == txtFieldState{
txtFieldState.inputView = picker
txtFieldState.inputAccessoryView = toolBar
self.configurePicker()
}
}
func configurePicker()
{
picker.alpha = 1.0
picker.backgroundColor = UIColor(red:241/255.0, green:241/255.0, blue:241/255.0, alpha: 1.0)
picker.showsSelectionIndicator = true
picker.delegate = self
picker.selectedRowInComponent(0)
let screenRect = self.view.frame
let pickerSize = picker.sizeThatFits(CGSizeZero)
let x = screenRect.origin.x + (screenRect.size.width / 2) - (pickerSize.width / 2)
let pickerRect = CGRectMake(x,
screenRect.origin.y + (screenRect.size.height) - (pickerSize.height),
pickerSize.width,
pickerSize.height)
picker.frame = pickerRect
let toolbarSize = toolBar.sizeThatFits(CGSizeZero)
toolBar.frame = CGRectMake(x,pickerRect.origin.y, // right under the picker
pickerSize.width, // make them the same width
toolbarSize.height)
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int){
dropState = row
txtFieldState.text = "\(stateArray[row])"
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
{
return stateArray[row]
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
{
return stateArray.count
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
{
return 1
}
}