Question

我正在尝试通过添加一个可以检测到掉落节点的位置来扩展我在Drag and drop example上学习的拖放示例。

从我尝试检测到掉落的节点开始，我了解到放下一个节点并期望它精确命中预定位置非常困难。

如何定义一个位置或像一个更大的矩形来检测放置的节点？

//: A SpriteKit based Playground

import PlaygroundSupport
import SpriteKit

class GameScene: SKScene {
private var currentNode: SKNode?

    override func didMove(to view: SKView) {
        let node = SKSpriteNode(
            color: .red,
            size: CGSize(width: 50, height: 50)
        )
        node.name = "draggable"
        self.addChild(node)

        let blueNode = SKSpriteNode(
            color: .blue,
            size: CGSize(width: 50, height: 50)
        )
        blueNode.name = "draggable"
        self.addChild(blueNode)

        let greenNode = SKSpriteNode(
            color: .green,
            size: CGSize(width: 50, height: 50)
        )
        greenNode.name = "droppable"
        greenNode.position = CGPoint(x: 100, y: 100)
        self.addChild(greenNode)

    }
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if let touch = touches.first {
            let location = touch.location(in: self)

            let touchedNodes = self.nodes(at: location)
            for node in touchedNodes.reversed() {
                if node.name == "draggable" {
                    self.currentNode = node
                }
            }
        }
    }
    @objc static override var supportsSecureCoding: Bool {
        // SKNode conforms to NSSecureCoding, so any subclass going
        // through the decoding process must support secure coding
        get {
            return true
        }
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

        if let touch = touches.first, let node = self.currentNode {
            let touchLocation = touch.location(in: self)
            node.position = touchLocation
        }

    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

        print(self.currentNode!.position);

        if self.currentNode!.position == CGPoint(x:100,y:100) {
            let yellowNode = SKSpriteNode(
                color: .yellow,
                size: CGSize(width: 50, height: 50)
            )
            yellowNode.name = "droppable"
            yellowNode.position = CGPoint(x: 200, y: 200)
            self.addChild(yellowNode)
        }
    }

    override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.currentNode = nil
    }

    override func update(_ currentTime: TimeInterval) {
        // Called before each frame is rendered
    }
}

// Load the SKScene from 'GameScene.sks'
let sceneView = SKView(frame: CGRect(x:0 , y:0, width: 640, height: 480))
if let scene = GameScene(fileNamed: "GameScene") {
    // Set the scale mode to scale to fit the window
    scene.scaleMode = .aspectFill

    // Present the scene
    sceneView.presentScene(scene)
}

PlaygroundSupport.PlaygroundPage.current.liveView = sceneView

Answer 1

我假设您正在touchesEnded(...)函数中寻求建议。

您是对的：就像在

中一样，检查位置是否正确

if self.currentNode!.position == CGPoint(x:100,y:100) {}

不会带你走得太远。手动点击屏幕上的特定点非常困难。

例如，您可以使用CGRect指定目标区域，然后检查触摸的位置是否在矩形内。

let targetRect = CGRect(x: 0, y: 0, width: 200, height: 200)
guard let node = self.currentNode else {return} // Just to avoid forced unwrapping
if targetRect.contains(node.position) {
    // Do stuff
}

我如何更好地定义一个区域来检测拖放的节点？

1 个答案: