Avoid button touches to be registered as swipe.

Questions & Answers
1

using UnityEngine;
using System.Collections;

public class TouchEventManager : MonoBehaviour {

	public float MinimumSwipeDist;
	public float ThresholdAngle;
	public delegate void GestureEventHandler();
	public static event GestureEventHandler OnSwipeRight;
	public static event GestureEventHandler OnSwipeLeft;
	public static event GestureEventHandler OnSwipeUp;
	public static event GestureEventHandler OnSwipeDown;

	private Vector2 mStartPos;
	
	// Update is called once per frame
	void Update () {
		if (Input.touchCount > 0) {
			Touch touch = Input.touches[0];
			
			switch(touch.phase) {
			case TouchPhase.Began:
				mStartPos = touch.position;
				break;
				
			case TouchPhase.Ended:
				float swipeDist = (touch.position - mStartPos).magnitude;
				// check if legal swipe
				if(swipeDist > MinimumSwipeDist) {
					determineSwipeType(touch.position);
				}
				break;
			}
		}
	}

	void determineSwipeType(Vector2 endPosition) {
		float angle = Vector2.Angle (Vector2.right, (endPosition - mStartPos));

		if (angle < ThresholdAngle) {
			// right swipe
			if(OnSwipeRight != null) {
				OnSwipeRight();
			}
		} else if(angle >= ThresholdAngle && angle <= 180 - ThresholdAngle) {
			float swipeValue = Mathf.Sign(endPosition.y - mStartPos.y);
			if(swipeValue > 0) {
				// up swipe
				if(OnSwipeUp != null) {
					OnSwipeUp();
				}
			} else {
				// down swipe
				if(OnSwipeDown != null) {
					OnSwipeDown();
				}
			}
		} else if(angle >= 180 - ThresholdAngle){
			// left swipe
			if(OnSwipeLeft != null) {
				OnSwipeLeft();
			}
		}
	}
}

I have the above code to detect swipe gesture in my game. I recently implemented some UI using the new UI system introduced in v4.6. I have a pause/resume button during gameplay and when I click on the buttons and make a small swipe motion while clicking, my swipe gesture code registers it and affects the gameplay. I have read, that I can do a raycast in my swipe gesture code to check if the touch hits any UI elements and if so not consider it as a swipe but I wanted to know if thats the standard way of doing it or I can somehow block events to my swipe code. I use Input.Touches in my swipe recognition which makes me believe that I will always have the touches in there even on UI buttons and might have to do some custom checking. If anyone knows of a better solution let me know. Also, feel free to use this code for your projects if anyone wants to. Thank you.

2

I solved this by casting a ray from the start position of the swipe and checking if its above any UI element. If the swipe starts above a UI element its discarded. Here is the piece of code that does this

private bool shouldDiscardSwipe(Vector2 touchPos) {
    		PointerEventData touch = new    PointerEventData(EventSystem.current);
    		touch.position = touchPos;
    		List<RaycastResult> hits = new List<RaycastResult>();
    		EventSystem.current.RaycastAll(touch, hits);
    		return (hits.Count > 0); // discard swipe if an UI element is beneath
    	}

Hope this helps someone.