Function to detect if there's any touch occurring on the screen - ios

Question

I'm trying to create a simple function, similar to the touchesBegan, that detects if there's any touch occurring on the screen.
I've hit a brick wall trying it out myself because I'm not comfortable with UITouch class, but I really need some self made function, outside the touchesBegan default one.
I was trying to do something like this 'pseudo-code/swift'
func isTouchingTheScreen() -> Bool {
let someTouchHandleConstant: uitouch ???
if imTouchingTheScreen {
return true
} else {
return false
}
}
Do you have any hints?
PS: I know that code doesn't work, don't call that out, it was just to give you some 'image' of what I was trying to do (:

Answer 1

The idea
You can simply keep track of every touch begun, ended or cancelled by the user.
class GameScene: SKScene {
private var activeTouches = Set<UITouch>()
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
activeTouches.unionInPlace(touches)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
activeTouches.subtractInPlace(touches)
}
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
if let touches = touches {
activeTouches.subtractInPlace(touches)
}
}
var isTouchingTheScreen: Bool { return !activeTouches.isEmpty }
}
Keeping activeTouches updated
As you can see I am keeping updated the activeTouches Set.
Every time a touch does begin I add it to activeTouches. And every time a touch does end or is cancelled I remove it from activeTouches.
The isTouchingTheScreen computed variable
This allows me to define the isTouchingTheScreen computed property that simply returns true when the Set contains some element.

Answer 2

You can implement UITapGestureRecognizer as below:
var tapGesture :UITapGestureRecognizer!
override func didMoveToNode() {
// Add UITapGestureRecognizer to view
self.tapGesture = UITapGestureRecognizer(target: self, action: #selector(ViewController.touchedView(_:)))
view.addGestureRecognizer(tapGesture)
}
func touchedView(sender: UITapGestureRecognizer) {
print("view touched")
}

Answer 3

You could implement UITapGestureRecognizer:
// global var
var tapGesture :UITapGestureRecognizer!
override func didMoveToView() {
// Add tap gesture recognizer to view
self.tapGesture = UITapGestureRecognizer(target: self, action: #selector(GameScene.handleTap(_:)))
self.tapGesture.cancelsTouchesInView = false
view.addGestureRecognizer(tapGesture)
}
func handleTap(sender: UITapGestureRecognizer) {
print("GameScene tap")
if sender.state == .Ended {
var positionInScene: CGPoint = sender.locationInView(sender.view)
positionInScene = self.scene!.convertPointFromView(positionInScene)
let touchedNode = self.nodeAtPoint(positionInScene)
if touchedNode.name != "myHero" {
print("The SKSpriteNode myHero was tapped")
}
}
}
You can find more details in Apple docs here.