ios swift Button, Label, AlertView

import UIKit



class ViewController: UIViewController , UIAlertViewDelegate {

@IBOutlet var label: UILabel?

@IBOutlet var btn: UIButton?



@IBAction func btnClick(AnyObject) {

    showAlert()

}



func showAlert() {

    let alert = UIAlertView()

    alert.title = "Alert"

    alert.delegate = self

    alert.message = "Hello Apple"

    alert.addButtonWithTitle("OK")

    alert.addButtonWithTitle("Cancel")

    alert.show()

}



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 alertView(alertView: UIAlertView!, clickedButtonAtIndex buttonIndex: Int) {

    switch buttonIndex

        {

    case 0:

        self.label?.text = "ok";

    case 1:

        self.label?.text = "cancel"

    default:

        println("alertView cancel!")

    }

}

}