Yield example

gistfile1.cs

using System.Collections.Generic;
using UnityEngine;
using System.Collections;

public class GuiTouchListener : RuntimeInteractiveObject
{
	const float SWIPE_MIN_LENGTH = 25.0f;
	const float TOUCH_BEGIN_DELAY = 0.03f;

	// Events methods names
	const string EVENT_TOUCHE_BEGIN = "OnGuiTouchBegin";
	const string EVENT_TOUCHE_DISMISS = "OnGuiTouchDismiss";
	const string EVENT_TOUCHE_END = "OnGuiTouchEnd";

	//**************************************************************************
	//
	// Runtime Interactive
	//
	//**************************************************************************

	//**************************************************************************
	// On touch begin

	public bool HandleTouchBegin(Vector3 position)
	{

		if (collide2DPoint(position)) {
			// StartCoroutine return immediately, without any delay, GuiTouchBegin will be called without delay too
			// But if "GuiTouchBegin" have "yield" expresion "StartCoroutine" will stuck on this expression until "yield retrun null"
			StartCoroutine(GuiTouchBegin(position, TOUCH_BEGIN_DELAY));
			// Important! No any delay return immediately
			return true;
		}
		
		return false;
	}
	
	//**************************************************************************
	// On touch move

	public bool HandleTouchMove(Vector3 position)
	{

		if (collide2DPoint(position))
		{
			Vector3 delta = position - tochBeginPosition;
			if (delta.magnitude > SWIPE_MIN_LENGTH)
			{
				GuiTouchDismiss();
			}
		} else
		{
			GuiTouchDismiss();
		}

		return true;
	}
	
	//**************************************************************************
	// On touch end

	public bool HandleTouchEnd(Vector3 position)
	{
		if (collide2DPoint(position))
		{
			GuiTouchEnded(position);
			return true;
		}

		return false;
	}

	//**************************************************************************
	//
	// Private
	//
	//**************************************************************************

	private Vector3 tochBeginPosition = Vector3.zero;
	private bool doActionAtTheEnd = false;
	private bool dismissToucheBegin = false;

	//**************************************************************************
	//
	// Send events to the game object components
	//
	//**************************************************************************

	private IEnumerator GuiTouchBegin(Vector3 position, float delay)
	{
		// Prepare object state
		dismissToucheBegin = false;
		doActionAtTheEnd = true;

		float pauseEndTime = Time.realtimeSinceStartup + delay; // Calculate end time

		// This while will do @delay@ seconds
		while(Time.realtimeSinceStartup < pauseEndTime) {
			yield return 0;
		}

		// When "yield return new WaitForSecond" after @delay seconds will return yield break, this line begin execute
		if(dismissToucheBegin) {
			yield break; // It dismiss code execution below, "yield break" not "return" because this method must return IEnumerator
		}

		tochBeginPosition = position;
		SendMessage(EVENT_TOUCHE_BEGIN, position, SendMessageOptions.RequireReceiver);
	}

	//--------------------------------------------------------------------------

	private void GuiTouchDismiss()
	{
		doActionAtTheEnd = false;
		dismissToucheBegin = true;
		SendMessage(EVENT_TOUCHE_DISMISS, SendMessageOptions.RequireReceiver);
	}

	//--------------------------------------------------------------------------

	private void GuiTouchEnded(Vector3 position)
	{
		dismissToucheBegin = true;
		if (!doActionAtTheEnd) return;
		SendMessage(EVENT_TOUCHE_END, position, SendMessageOptions.RequireReceiver);
	}

}