Sprite-Kit and Swift Update Position to Another Sprite - ios

Question

Like many here asking questions I'm new to programing, but I'm going to do my best to describe my dilemma. Thanks for any help in advance.
I've included a picture of my goal.
The Green line is a node that rotates around the center of the screen. I have its anchor point set to 1,1 and position x,y to the center of the device. Using SKActions I've made the node rotate so many degrees causing it to move like the second hand of a clock would around its center post. All the code to this point I've got down. Here is where I've reached a mental brick wall. I want to have a sprite constantly placed at the tip of the rotating node so that the sprite will move around the center in a circular motion. The sprite is represented by the Pink circle.
This was my plan of attack, but my lack of knowledge of the swift language prevents me from executing it.
Is there a way to add a reference point to the tip of the node? If so I was thinking of doing that, then in the update function set the position of the sprite to the x,y of that reference point. I hope I've included enough information. If anyone has a better approach to this, please let me hear it. Thanks so much in advance.

Answer 1

I am posting an answer, even though it was answered in the comments. If Leo posts the answer, I'll delete this one.
I am assuming that your ball is a child of the line, so you'd just offset the x position of your ball the width of the line. Which as noted in comments is the radius of the circle path your ball is following.
Your secondary issue could be solved by using another SKAction to offset the zRotation of the line. For example :
let lineRotateAction = SKAction.rotateByAngle(CGFloat(360).degreesToRadians, duration: 6)
let ballRotateAction = SKAction.rotateByAngle(CGFloat(-360).degreesToRadians, duration: 6)

Answer 2

You can simply put create the hands as children of an empty SKNode, position both hands correctly in relation to these SKNodes and then rotate the SKNodes themselves.

Answer 3

Two different ways: First using a parent node (which is potentially what you want):
let body = SKSpriteNode(color: .clear, size: CGSize(width: 20, height: 150))
body.anchorPoint = CGPoint(x: 0.5, y: 0)
body.position = CGPoint(x: frame.midX, y: frame.midY)
body.run(SKAction.repeatForever(SKAction.rotate(byAngle: CGFloat(M_PI * 2), duration: 10)))
let hand = SKSpriteNode(color: .blue, size: CGSize(width: body.size.width/2, height: body.size.height))
hand.position = CGPoint(x: 0, y: body.size.height/2)
let ball = SKSpriteNode(color: .green, size: CGSize(width: body.size.width, height: body.size.width))
ball.position = CGPoint(x: 0, y: body.size.height - ball.size.height/2)
body.addChild(hand)
body.addChild(ball)
addChild(body)
Second is using physics, which produces a similar effect only on the surface but it might give you other ideas too:
let hand = SKSpriteNode(color: .blue, size: CGSize(width: 10, height: 150))
hand.anchorPoint = CGPoint(x: 0.5, y: 1)
hand.position = CGPoint(x: frame.midX, y: frame.midY)
hand.physicsBody = SKPhysicsBody(rectangleOf: hand.size)
hand.physicsBody?.affectedByGravity = false
hand.physicsBody?.isDynamic = false
hand.run(SKAction.repeatForever(SKAction.rotate(byAngle: CGFloat(M_PI * 2), duration: 10)))
addChild(hand)
let ball = SKSpriteNode(color: .green, size: CGSize(width: 20, height: 20))
ball.anchorPoint = CGPoint(x: 0.5, y: 0.5)
ball.position = CGPoint(x: frame.midX, y: frame.midY - hand.size.height)
ball.physicsBody = SKPhysicsBody(rectangleOf: ball.size)
addChild(ball)
let joint = SKPhysicsJointPin.joint(withBodyA: hand.physicsBody!,
bodyB: ball.physicsBody!,
anchor: ball.position)
physicsWorld.add(joint)
Have fun!