swift - How to create a vertical scrolling menu in spritekit?

Question

I'm looking to create a shop in my game (In SpriteKit) with buttons and images, but I need the items to be scrollable so the player can scroll up and down the shop (Like a UITableView but with multiple SKSpriteNodes and SKLabelNodes in each cell). Any idea how I can do this in SpriteKit?

Answer 1

The second answer as promised, I just figured out the issue.

I recommend to always get the latest version of this code from my gitHub project incase I made changes since this answer, link is at the bottom.

Step 1: Create a new swift file and paste in this code

import SpriteKit

/// Scroll direction
enum ScrollDirection {
    case vertical // cases start with small letters as I am following Swift 3 guildlines.
    case horizontal
}

class CustomScrollView: UIScrollView {

// MARK: - Static Properties

/// Touches allowed
static var disabledTouches = false

/// Scroll view
private static var scrollView: UIScrollView!

// MARK: - Properties

/// Current scene
private let currentScene: SKScene

/// Moveable node
private let moveableNode: SKNode

/// Scroll direction
private let scrollDirection: ScrollDirection

/// Touched nodes
private var nodesTouched = [AnyObject]()

// MARK: - Init
init(frame: CGRect, scene: SKScene, moveableNode: SKNode) {
    self.currentScene = scene
    self.moveableNode = moveableNode
    self.scrollDirection = scrollDirection
    super.init(frame: frame)

    CustomScrollView.scrollView = self
    self.frame = frame
    delegate = self
    indicatorStyle = .White
    scrollEnabled = true
    userInteractionEnabled = true
    //canCancelContentTouches = false
    //self.minimumZoomScale = 1
    //self.maximumZoomScale = 3

    if scrollDirection == .horizontal {
        let flip = CGAffineTransformMakeScale(-1,-1)
        transform = flip
    }
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
   }
}

// MARK: - Touches
extension CustomScrollView {

/// Began
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

    for touch in touches {
        let location = touch.locationInNode(currentScene)

        guard !CustomScrollView.disabledTouches else { return }

        /// Call touches began in current scene
        currentScene.touchesBegan(touches, withEvent: event)

        /// Call touches began in all touched nodes in the current scene
        nodesTouched = currentScene.nodesAtPoint(location)
        for node in nodesTouched {
            node.touchesBegan(touches, withEvent: event)
        }
    }
}

/// Moved
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {

    for touch in touches {
        let location = touch.locationInNode(currentScene)

        guard !CustomScrollView.disabledTouches else { return }

        /// Call touches moved in current scene
        currentScene.touchesMoved(touches, withEvent: event)

        /// Call touches moved in all touched nodes in the current scene
        nodesTouched = currentScene.nodesAtPoint(location)
        for node in nodesTouched {
            node.touchesMoved(touches, withEvent: event)
        }
    }
}

/// Ended
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

    for touch in touches {
        let location = touch.locationInNode(currentScene)

        guard !CustomScrollView.disabledTouches else { return }

        /// Call touches ended in current scene
        currentScene.touchesEnded(touches, withEvent: event)

        /// Call touches ended in all touched nodes in the current scene
        nodesTouched = currentScene.nodesAtPoint(location)
        for node in nodesTouched {
            node.touchesEnded(touches, withEvent: event)
        }
    }
}

/// Cancelled
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {

    for touch in touches! {
        let location = touch.locationInNode(currentScene)

        guard !CustomScrollView.disabledTouches else { return }

        /// Call touches cancelled in current scene
        currentScene.touchesCancelled(touches, withEvent: event)

        /// Call touches cancelled in all touched nodes in the current scene
        nodesTouched = currentScene.nodesAtPoint(location)
        for node in nodesTouched {
            node.touchesCancelled(touches, withEvent: event)
        }
     }
   }
}

// MARK: - Touch Controls
extension CustomScrollView {

     /// Disable
    class func disable() {
        CustomScrollView.scrollView?.userInteractionEnabled = false
        CustomScrollView.disabledTouches = true
    }

    /// Enable
    class func enable() {
        CustomScrollView.scrollView?.userInteractionEnabled = true
        CustomScrollView.disabledTouches = false
    }
}

// MARK: - Delegates
extension CustomScrollView: UIScrollViewDelegate {

    func scrollViewDidScroll(scrollView: UIScrollView) {

        if scrollDirection == .horizontal {
            moveableNode.position.x = scrollView.contentOffset.x
        } else {
            moveableNode.position.y = scrollView.contentOffset.y
        }
    }
}

This make a subclass of UIScrollView and sets up the basic properties of it. It than has its own touches method which get passed along to the relevant scene.

Step2: In your relevant scene you want to use it you create a scroll view and moveable node property like so

weak var scrollView: CustomScrollView!
let moveableNode = SKNode()

and add them to the scene in didMoveToView

scrollView = CustomScrollView(frame: CGRect(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height), scene: self, moveableNode: moveableNode, scrollDirection: .vertical)
scrollView.contentSize = CGSizeMake(self.frame.size.width, self.frame.size.height * 2)
view?.addSubview(scrollView) 


addChild(moveableNode)

What you do here in line 1 is you init the scroll view helper with you scene dimensions. You also pass along the scene for reference and the moveableNode you created at step 2. Line 2 is where you set up the content size of the scrollView, in this case its twice as long as the screen height.

Step3: - Add you labels or nodes etc and position them.

label1.position.y = CGRectGetMidY(self.frame) - self.frame.size.height
moveableNode.addChild(label1)

in this example the label would be on the 2nd page in the scrollView. This is where you have to play around with you labels and positioning.

I recommend that if you have a lot pages in the scroll view and a lot of labels to do the following. Create a SKSpriteNode for each page in the scroll view and make each of them the size of the screen. Call them like page1Node, page2Node etc. You than add all the labels you want for example on the second page to page2Node. The benefit here is that you basically can position all your stuff as usual within page2Node and than just position page2Node in the scrollView.

You are also in luck because using the scrollView vertically (which u said you want) you dont need to do any flipping and reverse positioning.

I made some class func so if you need to disable your scrollView incase you overlay another menu ontop of the scrollView.

CustomScrollView.enable()
CustomScrollView.disable()

And finally do not forget to remove the scroll view from your scene before transitioning to a new one. One of the pains when dealing with UIKit in spritekit.

scrollView?.removeFromSuperView()

For horizontal scrolling simply change the scroll direction on the init method to .horizontal (step 2).

And now the biggest pain is that everything is in reverse when positioning stuff. So the scroll view goes from right to left. So you need to use the scrollView "contentOffset" method to reposition it and basically place all your labels in reverse order from right to left. Using SkNodes again makes this much easier once you understand whats happening.

Hope this helps and sorry for the massive post but as I said it is a bit of a pain in spritekit. Let me know how it goes and if I missed anything.

Project is on gitHub

https://github.com/crashoverride777/SwiftySKScrollView