Get touch type in hitTest() or pointInside()

Question

I'm implementing a passThroughView by creating a transparent View on top and override hitTest().

passThroughView should consume touches from Apple Pencil and if touch type is not from pencil, it pass touches to the view underneath.

The problems are:

parameter "event" in hitTest contains no touch, so I can't check touch type in hitTest
I can get touch from touchesBegan and check touch type, but it get called only after hitTest returned true
I subclass UIWindow and override sendEvent() but this function also called after hitTest (and I don't know why)

class WindowAbleToKnowTouchTypes: UIWindow {
    override func sendEvent(_ event: UIEvent) {
        if event.type == .touches {
            // This get called after Hittest
            if event.allTouches!.first!.type == .pencil {
                print("This touch is from Apple Pencil")
            }
        }
        super.sendEvent(event)
    }
}

Is there anyway to check touchType to decide to pass or consume touches?

Did you find a solution yet? I'm in the same situation… Seems like it is not possible. — ChaosCoder, Sep 28 '21 at 15:55
No, but you can check touch type in gestureRecognizer(UIGestureRecognizer, shouldReceive: UITouch). I think it could help in some cases — Brew Master, Sep 29 '21 at 19:40

score 2 · Answer 1 · answered Dec 01 '22 at 02:15

I ended up using a different approach, it could be useful for many cases: If I can't get touchType in hitTest(), I can still get the touchType with GestureRecognize:

class CustomGestureRecognizer : ImmediatePanGesture {
    var beganTouch : UITouch!
    var movedTouch : UITouch!
    var endedTouch : UITouch!

    override func shouldReceive(_ event: UIEvent) -> Bool {
        // You can check for touchType here and decide if this gesture should receice the touch or not
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
        // Save touch for later use
        if let firstTouch = touches.first {
            beganTouch = firstTouch
        }
        super.touchesBegan(touches, with: event)
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
        // Save touch for later use
        if let touch = touches.first {
            movedTouch = touch
        }
    
        super.touchesMoved(touches, with: event)
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
        // Save touch for later use
        if let touch = touches.first {
            endedTouch = touch
        }
    
        super.touchesEnded(touches, with: event)
    }
}

In the target function of the gestureRecognizer, you can get the UITouch by:

let beganTouch = customGesture.beganTouch
let touchType = beganTouch.touchType

Get touch type in hitTest() or pointInside()

1 Answers1