ANTM/Assets/NewScripts/UI/FlashEffect.cs

using UnityEngine;
using DG.Tweening;

public class FlashEffect : MonoBehaviour
{
	private static FlashEffect instance;
	private static Tween showTween;

	public CanvasGroup fill;

	private void Awake()
	{
		instance = this;
	}

	private void OnDestroy()
	{
		instance = null;
	}

	private void Start()
	{
		fill.alpha = 0.0f;
		fill.gameObject.SetActive(false);
	}

	public static void Flash()
	{
		if (showTween != null) showTween.Kill();

		// was causing a problem with getting started game tutorial
		// mock for it
		if (!instance)
			return;

		instance.fill.gameObject.SetActive(true);
		instance.fill.alpha = 1.0f;

		showTween = instance.fill.DOFade(0.0f, 0.7f)
			.SetEase(Ease.OutQuart)
			.OnComplete(OnFlashComplete);
	}

	private static void OnFlashComplete()
	{
		showTween = null;
		instance.fill.gameObject.SetActive(false);
	}
}