How do I detect if an SKSpriteNode has been touched

Question

First set the name property of the SKSpriteNode to a string.

pineapple.name = "pineapple"
pineapple.userInteractionEnabled = false

then in touchesBegan function in the Scene

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    let touch:UITouch = touches.anyObject()! as UITouch
    let positionInScene = touch.locationInNode(self)
    let touchedNode = self.nodeAtPoint(positionInScene)

    if let name = touchedNode.name
    {
        if name == "pineapple"
        {
            print("Touched")
        }
    }

}

This is one way to do it.
You can also subclass SKSpriteNode and override the touchesBegan inside it.

class TouchableSpriteNode : SKSpriteNode
{
    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        print("touched")
    }
}

Then do

let pineapple = TouchableSpriteNode(imageNamed: "Pineappleimg")
pineapple.userInteractionEnabled = true
pineapple.position = CGPoint(x: CGRectGetMidX(self.frame) - 200, y: CGRectGetMidY(self.frame));
self.addChild(pineapple)

If you are looking only for a few nodes that can be touched (e.g., the "Continue" or "Exit" labels in a game UI), this might be an alternative but very simple solution:

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    let touch = touches.first!
    if myNode.containsPoint(touch.locationInNode(self)) {
        print("touched")
    }
}

Update for Swift Swift version 3.0.2 (swiftlang-800.0.63 clang-800.0.42.1) and XCode Version 8.2.1 (8C1002):

Value of type 'Set' has no member 'anyObject'

'locationInNode' has been renamed to 'location(in:)'

'nodeAtPoint' has been renamed to 'atPoint(_:)'

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        let location = touch.location(in: self)
        let node : SKNode = self.atPoint(location)
        if node.name == "myNodeName" {
            print("Hello")
        }
    }
}

This will detect touches in Xcode 9.2 Swift 4.0

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?)
{
    let touch:UITouch = touches.first!
    let positionInScene = touch.location(in: self)
    let touchedNode = self.atPoint(positionInScene)

    if let name = touchedNode.name
    {
        if name == "playLbl"
        {
            print("playLbl Touched")
        }
    }

}