Error In Touches Began Function Sprite Kit

Question

Im trying make a redball in my XCode Poject move wherever my finger does. this is my code and It is not working. How would I fix my code?

import SpriteKit

class GameScene: SKScene {

let  redBall = SKSpriteNode(imageNamed: "redball")
var touching = false
var touchPoint: CGPoint = CGPoint()

override func didMoveToView(view: SKView) {

    //Middle Rectangle
    var mid = SKShapeNode(rectOfSize: CGSize(width: 50, height: 300))
    mid.physicsBody = SKPhysicsBody(edgeLoopFromRect: mid.frame)
    mid.physicsBody?.friction = 1
    mid.name = "middle"
    mid.fillColor = UIColor.whiteColor()
    mid.position = CGPointMake(self.size.width/2, self.size.height/2)
    addChild(mid)


    //World Border
    let worldBorder = SKPhysicsBody(edgeLoopFromRect: self.frame)
    self.physicsBody = worldBorder





    //RedBall
    let redBall = SKSpriteNode(imageNamed: "redball")
    redBall.physicsBody = SKPhysicsBody(circleOfRadius: redBall.size.width/2)
    redBall.physicsBody?.friction = 1
    redBall.physicsBody?.restitution = 1
    redBall.position = CGPointMake(self.size.width/4, self.size.height/2 + 20)
    addChild(redBall)


    //Paddle
    let paddle = SKShapeNode(rectOfSize: CGSize(width: 75, height: 20))
    paddle.physicsBody = SKPhysicsBody(edgeLoopFromRect: paddle.frame)
    paddle.position = CGPointMake(self.size.width/4 - 100 , self.size.height/3)
    addChild(paddle)

    //Physics World


    self.physicsWorld.gravity = CGVectorMake(0, 0)

}

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    let touch = touches.first as! UITouch
    let location = touch.locationInNode(self)
    println("hi")
    if location == redBall.position{
        redBall.position = location
        println("yo")


    }else{
        println("nothin")
    }


}

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {


}

override func update(currentTime: CFTimeInterval) {

}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {

}
override func touchesCancelled(touches: Set<NSObject>!, withEvent event: UIEvent!) {
}
}

I do not know why this code is not working how can I fix this thanks!

Answer 1

If the ball is to be situated at the position of your touch and is also supposed to move with your finger you probably need something like this:

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    let touch = touches.first as! UITouch
    redBall.position = touch.locationInNode(self)
}

This will reset the ball's position to the position of your touch.

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        let touch = touches.first as! UITouch
        redBall.position = touch.locationInNode(self)
}

And the exact same thing in touchesMoved will move the ball wherever your finger moves.

---

Also: There's a bug in your code. Your redBall property is never added to the scene, so that changing the position won't make a difference:

//RedBall
let redBall = SKSpriteNode(imageNamed: "redball") // <- this needs to go
redBall.physicsBody = SKPhysicsBody(circleOfRadius: redBall.size.width/2)
redBall.physicsBody?.friction = 1
redBall.physicsBody?.restitution = 1
redBall.position = CGPointMake(self.size.width/4, self.size.height/2 + 20)
addChild(redBall)

The above is a local scope sprite with the same name as your redBall-property. It is this node that is added to your scene, but you have no way of accessing it from elsewhere in the code. Remove let redBall = SKSpriteNode(imageNamed: "redball") from the above snippet and you should probably be up and running.