Swift Sprite-kit: Contact not registered after user interaction to move object - ios

Question

So I am having an issue with Swift Sprite-kit. Contact is not being registered. This has something to do with my code for moving a row of objects. I have code in the touchesBegan method that finds the user's touch location, and then a block of code in the touchesMoved method that then recognises a drag on the screen and moves the row correspondingly. I know that the touchesMoved function works because the row moves when the user drags the screen.
Here is the code for my touchesBegan method:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
if gameOver == 0 {
var touch = touches.first as! UITouch
var touchLocation = touch.locationInNode(self)
if let body = physicsWorld.bodyAtPoint(touchLocation) {
if body.node == self {
//if touchLocation == blueBox.position {
isFingerOnScreen = true
}
}
And this is my code for the touchesMoved
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
// 1. Check whether user touched the screen
if isFingerOnScreen == true {
// 2. Get touch location
var touch = touches.first as! UITouch
var touchLocation = touch.locationInNode(self)
var previousLocation = touch.previousLocationInNode(self)
// 4. Calculate new position along x for objects
var blueBoxX = blueBox.position.x + (touchLocation.x - previousLocation.x)
var greenBoxX = greenBox.position.x + (touchLocation.x - previousLocation.x)
var redBoxX = redBox.position.x + (touchLocation.x - previousLocation.x)
var yellowBoxX = yellowBox.position.x + (touchLocation.x - previousLocation.x)
// 5. Limit x so that the objects won't leave screen to left or right (this code does not actually work for me)
/*
blueBoxX = max(blueBoxX, blueBox.size.width/2)
blueBoxX = min(blueBoxX, size.width - blueBox.size.width/2)
greenBoxX = max(greenBoxX, greenBox.size.width/2)
greenBoxX = min(greenBoxX, size.width - greenBox.size.width/2)
redBoxX = max(redBoxX, redBox.size.width/2)
redBoxX = min(redBoxX, size.width - redBox.size.width/2)
yellowBoxX = max(yellowBoxX, yellowBox.size.width/2)
yellowBoxX = min(yellowBoxX, size.width - yellowBox.size.width/2)
*/
// 6. Update object position
blueBox.position = CGPointMake(blueBoxX, blueBox.position.y)
blueBox.zPosition = 10
greenBox.position = CGPointMake(greenBoxX, greenBox.position.y)
greenBox.zPosition = 10
greenBox.physicsBody = SKPhysicsBody(rectangleOfSize: CGSizeMake(greenBox.size.width, greenBox.size.height * 1/100))
greenBox.physicsBody!.dynamic = false
greenBox.physicsBody!.categoryBitMask = greenColourGroup
redBox.position = CGPointMake(redBoxX, redBox.position.y)
redBox.zPosition = 10
yellowBox.position = CGPointMake(yellowBoxX, yellowBox.position.y)
yellowBox.zPosition = 10
}
Now this is all good so far but my issue is that when this code is active, it for some reason stops the app from recognising contact between a ball and an object. Whereas when the code is commented out, the contact is recognised and the objects match. This makes no sense to me because as far as I can tell the only thing I am changing with the greenBox object (the only object I am testing with) is the position of the object in relation to the touchLocation.
My code for the contact is as follows:
func didBeginContact(contact: SKPhysicsContact) {
let contactMask = contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask
switch contactMask {
case greenColourGroup | ballColourGroup:
if contact.bodyA.categoryBitMask == greenColourGroup || contact.bodyB.categoryBitMask == greenColourGroup {
if ballColourGroup == greenColourGroup {
score++
scoreLabel.text = "\(score)"
ball.removeFromParent()
makeBall()
I am quite new to coding and am really struggling with this issue, so please help and if it involves code please include the necessary code needed to fix this issue.
Thanks
P.S: Just to confirm, the didBeginContact method works perfectly when the code for moving the objects is commented out, so I know that this code is ok. The issue is that the code within the touchesMoved method is stopping it from working