Touch Drag Inside a UIButton after 5 pixels instead of default 1 pixel

Question

I have a single UIButton on a storyboard. The UIButton is connected to a Touch Drag Inside action myTouchDragInsideAction. The action is triggered when a user drags the button from inside (UIControlEventTouchDragInside).

The problem is that the action is triggered after 1 pixel of inside dragging. However 1 pixel is too sensitive and can be triggered with just the slightest finger movement.

@IBAction func myTouchDragInsideAction(sender: UIButton) {

    print("Button dragged inside")

}

Question:

How can I extend this action to trigger the inside dragging action only after at least 5 pixels of movement?

score 2 · Accepted Answer · answered Apr 27 '16 at 11:05

You have to create custom button for it. Following CustomButton may help you.

let DelayPoint:CGFloat = 5

class CustomButton: UIButton {

    var startPoint:CGPoint?

    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {

        if self.startPoint == nil {
          self.startPoint = touches.first?.previousLocationInView(self)
        }


        if self.shouldAllowForSendActionForPoint((touches.first?.locationInView(self))!) {
            super.touchesMoved(touches, withEvent: event)
        }
    }

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        self.startPoint = nil
        super.touchesEnded(touches, withEvent: event)
    }

    func shouldAllowForSendActionForPoint(location:CGPoint) -> Bool {

        if self.startPoint != nil {

            let xDiff = (self.startPoint?.x)! - location.x
            let yDiff = (self.startPoint?.y)! - location.y

            if (xDiff > DelayPoint || xDiff < -DelayPoint || yDiff > DelayPoint || yDiff < -DelayPoint) {

                return true
            }
        }
        return false
    }
}

You change the "DelayPoint" as per your req. Hope this will help you.

Would be great if there was just a simple option for `Touch Drag Inside`, but this works just fine and doesn't interfere with my other connections. Thank you very much for your help! — user4806509, Apr 27 '16 at 15:38

score 0 · Answer 2 · edited May 23 '17 at 12:14

My implementation of solution for Swift 3

final class DraggedButton: UIButton {

    // MARK: - Public Properties
    @IBInspectable var sensitivityOfDrag: CGFloat = 5

    // MARK: - Private Properties
    private var startDragPoint: CGPoint?

    // MARK: - UIResponder
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        guard let firstTouch = touches.first else {
            return
        }

        let location = firstTouch.location(in: self)
        let previousLocation = firstTouch.previousLocation(in: self)

        if startDragPoint == nil {
            startDragPoint = previousLocation
        }

        if shouldAllowForSendActionForPoint(location: location) {
            super.touchesMoved(touches, with: event)
        }
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        startDragPoint = nil
        super.touchesEnded(touches, with: event)
    }

    // MARK: - Private methods
    private func shouldAllowForSendActionForPoint(location: CGPoint) -> Bool {
        guard let startDragPoint = startDragPoint else {
            return false
        }

        let xDifferent = abs(startDragPoint.x - location.x)
        let yDifferent = abs(startDragPoint.y - location.y)
        return xDifferent > sensitivityOfDrag || yDifferent > sensitivityOfDrag
    }
}

Touch Drag Inside a UIButton after 5 pixels instead of default 1 pixel

2 Answers2