How to use the selected value in UIPickerView - ios

Question

New to this, trying to create a simple app where user selects a birth year and a corresponding variable is shown.
i'd like the #IBAction func get to get the variable birthYear from the UiPicker at the bottom. I set the datasource and delegate for UIPicker to viewcontroller in the connections inspector panel.
class ViewController: UIViewController,UIPickerViewDelegate {
var years = ["1991", "1992", "1993", "1994", "1995", "1996", "1997", "1998", "1999"]
let nineOne = "24"
let nineTwo = "23"
let nineThree = "22"
let nineFour = "21"
let nineFive = "20"
let nineSix = "19"
let nineSeven = "18"
let zero = "17"
#IBAction func get(sender: AnyObject) {
if birthYear <= 1991
{
println(nineOne)
}
else if birthYear == 1992
{
println(nineTwo)
}else if birthYear == 1993{
println(nineThree)
}
else if birthYear == 1994{
println(nineFour)
}
else if birthYear == 1995{
println(nineFive)
}
else if birthYear == 1996{
println(nineSix)
}
else if birthYear == 1997{
println(nineSeven)
}
// current year minus 17
else if birthYear >= 1998 {
println(zero)
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
return years.count
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String!{
return years[row]
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
var birthYear = years[row]
}

Answer 1

If you don't know how to continue, here are 2 tutorials:
Displaying the result with a UILabel: http://makeapppie.com/tag/uipickerview-in-swift/
Displaying the result in UITextField: http://asanhussain.blogspot.ca/2012/11/uipickerview-in-uiactionsheet-for-iphone.html
Pay attention to the implementation for
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
}
Also, for UITextField implementation, needs to assign UIPickerView to inputView of UITextField.
=====================================================================
This is for your follow-up. There're 3 minor things to be noticed in your code.
First, you should connect an IBOutlet of UIPickerView to this View Controller. In your code, you connect a IBAction called get (which I think it's not very good as a function name) for some other view component.
Second, you didn't assign the delegate of picker view to the current view controller. So those delegate methods won't be called.
Third, birthYear's type is String. It can't be compared to Int directly.
Here is the revised code that will work if you connect PickerView in your storyboard to this IBOutlet. Hope it helps.
import UIKit
class ViewController: UIViewController,UIPickerViewDelegate {
#IBOutlet var pickerView: UIPickerView!
var years = ["1991", "1992", "1993", "1994", "1995", "1996", "1997", "1998", "1999"]
let nineOne = "24"
let nineTwo = "23"
let nineThree = "22"
let nineFour = "21"
let nineFive = "20"
let nineSix = "19"
let nineSeven = "18"
let zero = "17"
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
pickerView.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
return years.count
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String!{
return years[row]
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
var birthYear = years[row]
self.printYear(birthYear)
}
func printYear(birthYearString: String) {
if let birthYear = birthYearString.toInt() {
if birthYear <= 1991
{
println(nineOne)
}
else if birthYear == 1992
{
println(nineTwo)
}else if birthYear == 1993{
println(nineThree)
}
else if birthYear == 1994{
println(nineFour)
}
else if birthYear == 1995{
println(nineFive)
}
else if birthYear == 1996{
println(nineSix)
}
else if birthYear == 1997{
println(nineSeven)
}
// current year minus 17
else if birthYear >= 1998 {
println(zero)
}
}
}
}