quick and dirty dynamic pickerView in Swift 3

PickerViewController.swift

//
//  ViewController.swift
//  picker
//
//  Created by Slawomir Jasinski on 30/11/16.
//  Copyright © 2016 Slawomir Jasinski. All rights reserved.
//

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {

	// text fields
	@IBOutlet var tf_A: UITextField!
	@IBOutlet var tf_B: UITextField!
	
	// content for pickerViews
	let optionsA = ["Sunday" ,"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]
	let optionsB = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]
	
	
	// variables to gold current data
	var picker : UIPickerView!
	var activeTextField = 0
	var activeTF : UITextField!
	var activeValue = ""
	
	override func viewDidLoad() {
		super.viewDidLoad()

		// delegates for text fields
		tf_A.delegate = self
		tf_B.delegate = self
	}

	override func didReceiveMemoryWarning() {
		super.didReceiveMemoryWarning()
		// Dispose of any resources that can be recreated.
	}

	// number of components in picekr view
	func numberOfComponents(in pickerView: UIPickerView) -> Int {
		return 1
	}
	
	// return number of elements in picker view
	func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
		
		// get number of elements in each pickerview
		switch activeTextField {
			case 1:
				return optionsA.count
			case 2:
				return optionsB.count
			default:
				return 0
		}
	}
	
	// return "content" for picker view
	func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
		
		// return correct content for picekr view
		switch activeTextField {
			case 1:
				return optionsA[row]
			case 2:
				return optionsB[row]
			default:
				return ""
		}
		
	}
	
	// get currect value for picker view
	func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
		
		// set currect active value based on picker view
		switch activeTextField {
			case 1:
				activeValue = optionsA[row]
			case 2:
				activeValue = optionsB[row]
			default:
				activeValue = ""
		}
	}
	
	// start editing text field
	func textFieldDidBeginEditing(_ textField: UITextField) {
		
		// set up correct active textField (no)
		switch textField {
			case tf_A:
				activeTextField = 1
			case tf_B:
				activeTextField = 2
			default:
				activeTextField = 0
		}
		
		// set active Text Field
		activeTF = textField
		
		self.pickUpValue(textField: textField)
		
	}
	
	// show picker view
	func pickUpValue(textField: UITextField) {
		
		// create frame and size of picker view
		picker = UIPickerView(frame:CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: self.view.frame.size.width, height: 216)))
		
		// deletates
		picker.delegate = self
		picker.dataSource = self

		// if there is a value in current text field, try to find it existing list
		if let currentValue = textField.text {
			
			var row : Int?
		
			// look in correct array
			switch activeTextField {
				case 1:
					row = optionsA.index(of: currentValue)
				case 2:
					row = optionsB.index(of: currentValue)
				default:
					row = nil
			}
			
			// we got it, let's set select it
			if row != nil {
				picker.selectRow(row!, inComponent: 0, animated: true)
			}
		}
		
		picker.backgroundColor = UIColor.white
		textField.inputView = self.picker
		
		// toolBar
		let toolBar = UIToolbar()
		toolBar.barStyle = .default
		toolBar.isTranslucent = true
		toolBar.barTintColor = UIColor.darkGray
		toolBar.sizeToFit()
		
		// buttons for toolBar
		let doneButton = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(doneClick))
		let spaceButton = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
		let cancelButton = UIBarButtonItem(title: "Cancel", style: .plain, target: self, action: #selector(cancelClick))
		toolBar.setItems([cancelButton, spaceButton, doneButton], animated: false)
		toolBar.isUserInteractionEnabled = true
		textField.inputAccessoryView = toolBar

	}
	
	// done
	func doneClick() {
		activeTF.text = activeValue
		activeTF.resignFirstResponder()

	}
	
	// cancel
	func cancelClick() {
		activeTF.resignFirstResponder()
	}

}