ios - 在 SpriteKit 中模拟 UIScrollView : scrolling SKScene works when SKView is 2000 points tall but fails when height is 2050

Question

目标是滚动 SKScene，其行为与 UIScrollView 相同。

其他问题类似，但答案没有帮助。

此代码说明了当 SKView subview 高 2000 点时 UIScrollView + SKView 如何显示内容，但如果 subview 高 2050 点则什么也不显示。

高度很重要，因为例如，如果 SKScene 包含 3000 点高的节点图，我们需要在 UIScrollView 中渲染场景(通过在 SKView 内呈现场景，SKView 本身就是 UIScrollView 的 subview ) .

class TestViewController: UIViewController, UIScrollViewDelegate {

    @IBOutlet weak var scrollView: UIScrollView!

    override func viewDidLoad() {
        // Call super
        super.viewDidLoad()

        // Make scene (then someone call the police)
        let scene = TestScene(size: UIScreen.main.bounds.size)

        // Allow other overlays to get presented
        definesPresentationContext = true

        // Set background color
        scrollView.backgroundColor = UIColor.clear

        // Create content view for scrolling since SKViews vanish with height > 2050
        let contentHeight = scene.getScrollHeight()
        let contentFrame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: contentHeight)
        let contentView = UIView(frame: contentFrame)
        contentView.backgroundColor = UIColor.clear

        // Create SKView
        let skFrame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: contentHeight)
        let skView = SKView(frame: skFrame)

        // Configure <scrollView>
        scrollView.insertSubview(skView, at: 0)
        scrollView.addSubview(contentView)
        scrollView.delegate = self
        scrollView.contentSize = contentFrame.size

        // Present scene
        skView.presentScene(scene)
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        scene.scrollBy(offset: scrollView.contentOffset.y)
    }
}

Answer 1

这两个类演示了如何使用 UIScrollView 行为滚动 SKScene 菜单或场景。

感谢@KnightofDragon 发现了代码中的关键缺陷。

令人沮丧的是，Apple 本身并未提供此功能，但希望其他人不必浪费时间尝试在 SpriteKit 中实现菜单滚动的最佳方法!

UIViewController 假定 UIScrollView 已通过 Storyboard 添加。

class ScrollViewController: UIViewController, UIScrollViewDelegate {
    // IB Outlets
    @IBOutlet weak var scrollView: UIScrollView!

    // General Vars
    var scene = ScrollScene()

    // =======================================================================================================
    // MARK: Public Functions
    // =======================================================================================================
    override func viewDidLoad() {
        // Call super
        super.viewDidLoad()

        // Create scene
        scene = ScrollScene()

        // Allow other overlays to get presented
        definesPresentationContext = true

        // Create content view for scrolling since SKViews vanish with height > ~2048
        let contentHeight = scene.getScrollHeight()
        let contentFrame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: contentHeight)
        let contentView = UIView(frame: contentFrame)
        contentView.backgroundColor = UIColor.clear

        // Create SKView with same frame as <scrollView>, must manually compute because <scrollView> frame not ready at this point
        let scrollViewPosY = CGFloat(0)
        let scrollViewHeight = UIScreen.main.bounds.size.height - scrollViewPosY
        let scrollViewFrame = CGRect(x: 0, y: scrollViewPosY, width: UIScreen.main.bounds.size.width, height: scrollViewHeight)
        let skView = SKView(frame: scrollViewFrame)
        view.insertSubview(skView, at: 0)

        // Configure <scrollView>
        scrollView.addSubview(contentView)
        scrollView.delegate = self
        scrollView.contentSize = contentFrame.size

        // Present scene
        skView.presentScene(scene)

        // Handle taps on <scrollView>
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(scrollViewDidTap))
        scrollView.addGestureRecognizer(tapGesture)
    }

    // =======================================================================================================
    // MARK: UIScrollViewDelegate Functions
    // =======================================================================================================
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        scene.scrollBy(contentOffset: scrollView.contentOffset.y)
    }


    // =======================================================================================================
    // MARK: Gesture Functions
    // =======================================================================================================
    @objc func scrollViewDidTap(_ sender: UITapGestureRecognizer) {
        let scrollViewPoint = sender.location(in: sender.view!)
        scene.viewDidTapPoint(viewPoint: scrollViewPoint, contentOffset: scrollView.contentOffset.y)
    }
}



class ScrollScene : SKScene {
    // Layer Vars
    let scrollLayer = SKNode()

    // General Vars
    var originalPosY = CGFloat(0)


    // ================================================================================================
    // MARK: Initializers
    // ================================================================================================
    override init() {
        super.init()
    }


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


    // ================================================================================================
    // MARK: Public Functions
    // ================================================================================================
    func scrollBy(contentOffset: CGFloat) {
        scrollLayer.position.y = originalPosY + contentOffset
    }


    func viewDidTapPoint(viewPoint: CGPoint, contentOffset: CGFloat) {
        let nodes = getNodesTouchedFromView(point: viewPoint, contentOffset: contentOffset)
    }


    func getScrollHeight() -> CGFloat {
        return scrollLayer.calculateAccumulatedFrame().height
    }


    fileprivate func getNodesTouchedFromView(point: CGPoint, contentOffset: CGFloat) -> [SKNode] {
        var scenePoint = convertPoint(fromView: point)
        scenePoint.y += contentOffset
        return scrollLayer.nodes(at: scenePoint)
    }
}