UIButton help in Swift

Question

Im trying to program a UIButton that performs that prints a message to the console. I can see the button and touch it but as soon as I touch it my app stops running and the console shows the following error:

Game[2743:63724] -[Game.GameScene buttonAction:]: unrecognized selector sent to instance 0x7a11ad00
2014-09-15 17:51:06.106 Game[2743:63724] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[GameGameScene buttonAction:]: unrecognized selector sent to instance 0x7a11ad00' 

this is my code:

    let imageButton = UIImage(named: "playbutton2") as UIImage
    let buttonPlay = UIButton.buttonWithType(UIButtonType.Custom) as UIButton
    buttonPlay.frame = CGRectMake(screenSize.width / 2 , screenSize.height / 2, 100, 100)
    buttonPlay.setImage(imageButton, forState: .Normal)
    buttonPlay.addTarget(self, action: Selector("buttonAction:"), forControlEvents: UIControlEvents.TouchUpInside)
    buttonPlay.tag = 22
    self.view.addSubview(buttonPlay)

and

    func buttonAction(sender:UIButton!) {
        println("Button tapped") 
    }

------- COMPLETE CODE ---------

import SpriteKit

class GameScene: SKScene {

    var skyColor = SKColor()
    var bird = SKSpriteNode()
    var moving = SKNode()
    var titleLabelNode = SKLabelNode()
    var title = NSString()
    let imageButton = UIImage(named: "playbutton2") as UIImage

    let screenSize: CGRect = UIScreen.mainScreen().bounds



    override func didMoveToView(view: SKView) {
        /* Setup your scene here */

        self.addChild(moving)
        skyColor = SKColor(red: 113.0/255.0, green: 197.0/255.0, blue: 207.0/255.0, alpha: 1.0)
        self.backgroundColor = skyColor

        var birdTexture1 = SKTexture(imageNamed: "Bird1")
        birdTexture1.filteringMode = SKTextureFilteringMode.Nearest

        var birdTexture2 = SKTexture(imageNamed: "Bird2")
        birdTexture2.filteringMode = SKTextureFilteringMode.Nearest

        var animation = SKAction.animateWithTextures([birdTexture1, birdTexture2], timePerFrame: 0.2)
        var flap = SKAction.repeatActionForever(animation)

        bird = SKSpriteNode(texture: birdTexture1)
        bird.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame) + 150)
        bird.runAction(flap)

        bird.physicsBody = SKPhysicsBody(circleOfRadius: bird.size.height/2.0)
        bird.physicsBody.dynamic = false
        self.addChild(bird)

        var groundTexture = SKTexture(imageNamed: "Ground")
        groundTexture.filteringMode = SKTextureFilteringMode.Nearest

        var moveGroundSprite = SKAction.moveByX(-groundTexture.size().width, y: 0, duration: NSTimeInterval(0.01 * groundTexture.size().width))
        var resetGroundSprite = SKAction.moveByX(groundTexture.size().width, y: 0, duration: 0)
        var moveGroundSpritesForever = SKAction.repeatActionForever(SKAction.sequence([moveGroundSprite, resetGroundSprite]))
        for var i:CGFloat = 0; i<2 + self.frame.size.width / (groundTexture.size().width); ++i {
            var sprite = SKSpriteNode(texture: groundTexture)
            sprite.position = CGPointMake(i * sprite.size.width, sprite.size.height / 2)
            sprite.runAction(moveGroundSpritesForever)
            moving.addChild(sprite)


        }
        title = "Swing Bird"

        titleLabelNode.fontName = "Helvetica-Bold"
        titleLabelNode.fontSize = 80
        //titleLabelNode.fontColor = SKColor(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.)
        titleLabelNode.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame) + 50)
        titleLabelNode.text = "\(title)"
        addChild(titleLabelNode)




        let buttonPlay = UIButton.buttonWithType(UIButtonType.Custom) as UIButton
        buttonPlay.frame = CGRectMake(screenSize.width / 2 , screenSize.height / 2, 100, 100)
        buttonPlay.setImage(imageButton, forState: .Normal)
        buttonPlay.addTarget(self, action: Selector("buttonAction:"), forControlEvents: UIControlEvents.TouchUpInside)
        buttonPlay.tag = 22
        self.view.addSubview(buttonPlay)


        func buttonAction(sender:UIButton!) {



            println("Button tapped")

        }

    }

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        /* Called when a touch begins */

           }

    override func update(currentTime: CFTimeInterval) {
        /* Called before each frame is rendered */
    }
}

Answer 1

Your function buttonAction is defined at the wrong level. It is currently a function inside didMoveToView instead of a function of the class GameScene.

You can fix it like this:

class GameScene: SKScene {

    ...

    // Move the function here!
    func buttonAction(sender:UIButton!) {



            println("Button tapped")

    }

    override func didMoveToView(view: SKView) {
         ...