XRLib/Assets/Scripts/UVC/UI/Loading/UILoading.cs

using System.Collections;
using UnityEngine;
using UnityEngine.UI;

namespace UVC.UI.Loading
{
    [RequireComponent(typeof(CanvasGroup))]
    public class UILoading : UnityEngine.MonoBehaviour
    {
        public static string PrefabPath = "Prefabs/UI/Loading/UILoading";

        private static UILoading instance;

        public static void Show()
        {
            if (instance == null) { 
                GameObject prefab = Resources.Load<GameObject>(PrefabPath);
                GameObject go = Instantiate(prefab);
                go.name = "UILoading";
                go.transform.SetParent(null, false);
                instance = go.GetComponent<UILoading>();
            }
            instance.ShowLoading();
        }

        public static void Hide()
        {
            if (instance != null)
            {
                instance.HideLoading();
            }
        }


        private CanvasGroup canvasGroup;
        private float target = 0;
        private float duration = 0.25f;
        private float alpha = 1;
        private bool animatting = false;
        private Image loadinImage;
        private Transform loadingImageTransform;

        private float loadingSpeed = 1.5f;
        private float rotationSpeed = 1.0f;

        private void Awake()
        {
            canvasGroup = GetComponent<CanvasGroup>();
            loadinImage = transform.Find("loadingImage").GetComponent<Image>();
            loadingImageTransform = loadinImage.transform;
            
        }


        public void ShowLoading()
        {
            if (animatting && target == 1) return;

            target = 1;
            animatting = true;
            StopCoroutine("Animate");
            StartCoroutine(Animate());
        }

        public void HideLoading()
        {
            if (animatting && target == 0) return;

            target = 0;
            animatting = true;
            StopCoroutine("Animate");
            StartCoroutine(Animate());
        }

        private IEnumerator Animate()
        {
            float start = canvasGroup.alpha;
            float time = 0;

            while (time < duration)
            {
                time += Time.deltaTime;
                canvasGroup.alpha = Mathf.Lerp(start, target, time / duration);
                yield return null;
            }

            canvasGroup.alpha = target;
            animatting = false;
            if(target == 0)
            {
                Destroy(gameObject);
            }
        }

        private void Update()
        {
            if (canvasGroup.alpha == 1)
            {
                loadingImageTransform.Rotate(Vector3.forward, loadingSpeed * Time.deltaTime * 360);
                loadinImage.fillAmount = Mathf.PingPong(Time.time * rotationSpeed, 1);
            }
        }
    }
}