Custom UIButton .touchDragEnter and .touchDragExit area/size?

Question

Is it possible to customize the area from the button at which it is considered .touchDragExit (or .touchDragEnter) (out of its selectable area?)?

To be more specific, I am speaking about this situation: I tap the UIButton, the .touchDown gets called, then I start dragging my finger away from the button and at some point (some distance away) it will not select anymore (and of course I can drag back in to select...). I would like the modify that distance...

Is this even possible?

I think the following may help: https://stackoverflow.com/a/38335868/35499 — Dean, Jul 22 '19 at 21:34
@Dean how exactly would I implement the above Swift answer (which is an old version of Swift) — , Jul 22 '19 at 22:18

score 5 · Accepted Answer · answered Jul 23 '19 at 18:09

You need to overwrite the UIButton continueTracking and touchesEnded functions.

Adapting @Dean's link, the implementation would be as following (swift 4.2):

class ViewController: UIViewController {

    @IBOutlet weak var button: DragButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

}

class DragButton: UIButton {

    private let _boundsExtension: CGFloat = 0 // Adjust this as needed

    override open func continueTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {

        let outerBounds: CGRect = bounds.insetBy(dx: CGFloat(-1 * _boundsExtension), dy: CGFloat(-1 * _boundsExtension))

        let currentLocation: CGPoint = touch.location(in: self)
        let previousLocation: CGPoint = touch.previousLocation(in: self)

        let touchOutside: Bool = !outerBounds.contains(currentLocation)
        if touchOutside {
            let previousTouchInside: Bool = outerBounds.contains(previousLocation)
            if previousTouchInside {
                print("touchDragExit")
                sendActions(for: .touchDragExit)
            } else {
                print("touchDragOutside")
                sendActions(for: .touchDragOutside)
            }
        } else {
            let previousTouchOutside: Bool = !outerBounds.contains(previousLocation)
            if previousTouchOutside {
                print("touchDragEnter")
                sendActions(for: .touchDragEnter)
            } else {
                print("touchDragInside")
                sendActions(for: .touchDragInside)
            }
        }

        return true
    }

    override open func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

        let touch: UITouch = touches.first!
        let outerBounds: CGRect = bounds.insetBy(dx: CGFloat(-1 * _boundsExtension), dy: CGFloat(-1 * _boundsExtension))

        let currentLocation: CGPoint = touch.location(in: self)

        let touchInside: Bool = outerBounds.contains(currentLocation)
        if touchInside {
            print("touchUpInside action")
            return sendActions(for: .touchUpInside)
        } else {
            print("touchUpOutside action")
            return sendActions(for: .touchUpOutside)
        }
    }
}

Try changing the _boundsExtension value

score 1 · Answer 2 · answered Jul 29 '19 at 08:38

1

The drag area is exaclty equal to the area define by bounds. So if you want to customize the drag are simple customise the bounds of your button.

answered Jul 29 '19 at 08:38

Abhishek Maurya

697
7
19

And how would I change the bounds of the UIButton – Jul 29 '19 at 17:07

Custom UIButton .touchDragEnter and .touchDragExit area/size?

2 Answers2