How to make an UIPickerView with a Done button?

Add this code to your viewDidLoad() instead of method

let picker: UIPickerView
picker = UIPickerView(frame: CGRectMake(0, 200, view.frame.width, 300))
picker.backgroundColor = .whiteColor()

picker.showsSelectionIndicator = true
picker.delegate = self
picker.dataSource = self

let toolBar = UIToolbar()
toolBar.barStyle = UIBarStyle.default
toolBar.isTranslucent = true
toolBar.tintColor = UIColor(red: 76/255, green: 217/255, blue: 100/255, alpha: 1)
toolBar.sizeToFit()

let doneButton = UIBarButtonItem(title: "Done", style: UIBarButtonItem.Style.done, target: self, action: #selector(self. donePicker))
let spaceButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.flexibleSpace, target: nil, action: nil)
let cancelButton = UIBarButtonItem(title: "Cancel", style: UIBarButtonItem.Style.plain, target: self, action: #selector(self. donePicker))

toolBar.setItems([cancelButton, spaceButton, doneButton], animated: false)
toolBar.userInteractionEnabled = true

textField1.inputView = picker
textField1.inputAccessoryView = toolBar