swiftswiftuisprite-kittouchesbeganspriteview

SKScene touchesBegan only registering first touch when presented from SpriteView


I'm using SwiftUI and trying to implement touchesBegan method from an SKScene object so that touches on the left half of a SpriteView create a green box, and touches on the right half create a red box. This works to a point, but cannot handle multiple simultaneous touches. It seems to work fine when not run from within a SwiftUI SpriteView (i.e. when presented by an SKView of a UIViewController). Here's my GameScene.swift...

import SwiftUI
import SpriteKit

class GameScene: SKScene {
    override func didMove(to view: SKView) {
        physicsBody = SKPhysicsBody(edgeLoopFrom: frame)
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches {
            let colour: SKColor
            let location = touch.location(in: self)
            if location.x > self.frame.midX {
                print("right")
                colour = .red
            }
            else {
                print("left")
                colour = .green
            }
            let box = SKSpriteNode(color: colour, size: CGSize(width: 50, height: 50))
            box.position = location
            box.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: 50, height: 50))
            addChild(box)
        }
    }
}

...and my ContentView.swift...

import SwiftUI
import SpriteKit

struct ContentView: View {
    var scene: SKScene {
        let scene = GameScene()
        scene.size = CGSize(width: 500, height: 350)
        scene.scaleMode = .fill
        return scene
    }
    
    var body: some View {
        SpriteView(scene: scene)
            .frame(width: 500, height: 350)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Any ideas?


Solution

  • Solution:

    1. Add 'view.isMultipleTouchEnabled = true' to GameScene.didMove(to view:)

    Need to know:

    1. UIView has property 'isMultipleTouchEnabled'.
    2. SKView is inherited from UIView.
    3. The default value of this property is false.