UILongPressGestureRecognizer with SpriteKit

Question

I'm trying to figure it out how to detect if a shapeNode has been pressed, specifically with the LongPress Gesture. Please take a look on the below code. Any idea what is wrong, why I can't see the "Found!" message?

class Test: SKScene {
    let longPressGesture = UILongPressGestureRecognizer()

    override func didMove(to view: SKView) {

        longPressGesture.addTarget(self, action: #selector(GameScene.longPress))
        self.view?.addGestureRecognizer(longPressGesture)

        let testPath = UIBezierPath(rect: CGRect(x: (view.scene?.frame.midX)!, y: (view.scene?.frame.midY)!, width: 2 * 50.0, height: 2 * 50.0)).cgPath

        let testNode = Node.init(path: testPath, nodeName: "TEST")
        testNode.fillColor = UIColor.brown
        testNode.position = CGPoint(x: (view.scene?.frame.midX)!, y: (view.scene?.frame.midY)!)

        self.addChild(testNode)
    }

    func longPress(_ sender: UILongPressGestureRecognizer) {
        let longPressLocation = sender.location(in: self.view)

        if sender.state == .began {
            for child in self.children {
                if let shapeNode = child as? SKShapeNode {
                    if shapeNode.contains(longPressLocation) {
                        print("Found!")   
                    }
                }
            }
        } else if sender.state == .ended {
            print("ended")
        }
    }
}

Many thanks for any help!

i may be wrong, but you are doing `view.scene?.frame` when you can just do `.frame` :) — Fluidity, Jul 04 '17 at 00:05

score 2 · Accepted Answer · answered Jul 03 '17 at 20:53

2

You are currently calculating tap location in view's coordinate system. In order to work in scene's coordinate system (because SKShapeNode is added to a scene), you have to convert a tap location from view's coordinate system to scene's coordinate system, like this:

let longPressLocation = convertPoint(fromView: sender.location(in: self.view))

Unrelated to original issue, but a good thing to keep in mind is that forced unwrapping is not that good idea most of the time (sometimes it helps while development phase though), and you should tend to access underlying values of an optionals in a safe way ( using if let syntax for example).

answered Jul 03 '17 at 20:53

Whirlwind

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ugh, always force unwrap `.view`. So annoying to guard for that. – Fluidity Jul 04 '17 at 00:06
1

... there is reason behind it, what if you are transitioning scenes? force unwrap would crash your app – Knight0fDragon Jul 04 '17 at 01:05
1

@Whirlwind, this perfecly solves my problem. Thank you so much! – RafalK Jul 04 '17 at 04:14

UILongPressGestureRecognizer with SpriteKit

1 Answers1