Multi-touch gesture in Sprite Kit

Question

I\'m working in Swift with Sprite-Kit using XCode 6, and I have many different nodes but for the moment I only manage to detect one finger and move one node at the same time

Answer 1

Moving multiple nodes simultaneously is fairly straightforward. The key is to track each touch event independently. One way to do that is to maintain a dictionary that uses the touch event as the key and the node being moved as the value.

First, declare the dictionary

var selectedNodes:[UITouch:SKSpriteNode] = [:]

Add each sprite touched to the dictionary with the touch event as the key

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        let location = touch.location(in:self)
        if let node = self.atPoint(location) as? SKSpriteNode {
            // Assumes sprites are named "sprite"
            if (node.name == "sprite") {
                selectedNodes[touch] = node
            }
        }
    }
}

Update the positions of the sprites as needed

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        let location = touch.location(in:self)
        // Update the position of the sprites
        if let node = selectedNodes[touch] {
            node.position = location
        }
    }
}

Remove the sprite from the dictionary when the touch ends

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        if selectedNodes[touch] != nil {
            selectedNodes[touch] = nil
        }
    }
}