How to implement touchesBegan in a C4View?

[cadin]

What's the recommended method for implementing touchesBegan, touchesMoved, etc from within a View subclass? Since View doesn't inherit from UIView, they're not called automatically.

[travis]

hey cadin,

Does your implementation specifically require touchesBegan, etc? Or can you get away with using our gesture approach:

    let tg = canvas.addTapGestureRecognizer { locations, center, state in
        //do stuff here
    }

?

[travis]

p.s. sorry for the delay in responding, had a hectic weekend.

[cadin]

I'd like to be able to detect when a finger touches down (to light up the object being touched, for example). I don't think a tap gesture will work there because it only triggers after the touch is lifted (or not at all in the case of touch-and-hold).

[travis]

A long press with miniumDuration = 0 is what you're looking for.

let obj = Circle(center: canvas.center, radius: 100)
let lp = obj.addLongPressGestureRecognizer { locations, center, state in
    switch state {
    case .Began:
        obj.fillColor = C4Pink
    case .Ended:
        obj.fillColor = C4Blue
    default:
        break
    }
}
lp.minimumPressDuration = 0.0
canvas.add(obj)

Here's a GIST with the above example working. It also attaches the same kind of gesture to the canvas.

The long press gesture will give you the opportunity to hit test the object as well, i.e. if you want to change the highlight when the touch drags out / leaves the frame of the object.