LoadingScreen.cs

using UnityEngine;
using UnityEngine.SceneManagement;
using System.Collections;
using DG.Tweening;
using UnityEngine.UI;

/* 
    UnityAction<Scene, Scene> activeSceneChanged;
    UnityAction<Scene, LoadSceneMode> sceneLoaded;
    UnityAction<Scene> sceneUnloaded;
 */

public class LoadingScreen : MonoBehaviour
{
    public Image _thisImage;
    public RectTransform _spinRect;
    public static LoadingScreen _instance;
	RectTransform _thisRect;
    float _imageHeight;
    Sequence _loadingScreen;
    bool _isHidden = true;

    void Awake () {
        if (_instance == null) {
            _instance = this;
            DontDestroyOnLoad(gameObject);
            SceneManager.sceneLoaded += SceneLoaded;
            // SceneManager.activeSceneChanged += SceneChange;
        } else {
            Destroy(gameObject);
        }
	    _thisRect = _thisImage.GetComponent<RectTransform>();
        _imageHeight = GetComponent<Canvas>().rectTransform().sizeDelta.y;
    }

    void Start() {
        Debug.Log(_thisRect.anchoredPosition);
        _thisRect.anchoredPosition = new Vector2(_thisRect.anchoredPosition.x, 0f);
        _loadingScreen = DOTween.Sequence().SetAutoKill(false).Pause();
        _loadingScreen.Append(_thisRect.DOAnchorPosY(_imageHeight, 0.3f).SetEase(Ease.Linear));
        // _thisRect.anchoredPosition = Vector2.zero;
        _loadingScreen.PlayForward();
        // _loadingScreen.Append(_thisRect.DOAnchorPosY(0f, 0.3f).SetEase(Ease.InCubic)).Insert(0f, _rectRotatingImage.DOLocalRotate(new Vector3(0f, 0f, 90f), 1f, RotateMode.Fast).SetEase(Ease.Linear).SetLoops(-1, LoopType.Incremental)
        // );
    }

    void LoadingScreenSwitch () {
        if (_isHidden) {
            _loadingScreen.PlayBackwards();
        } else {
            _loadingScreen.PlayForward();
        }
        _isHidden = !_isHidden;
        Debug.Log("Loading Screen");
	}

    public void LoadScene (string scene) {
        StartCoroutine("PlayBackwardsSequence", scene);
    }

    IEnumerator PlayBackwardsSequence (string scene) {
        _loadingScreen.PlayBackwards();
        yield return new WaitForSeconds(0.3f);
        SceneManager.LoadSceneAsync(scene);
    }

    void SceneChange (Scene previousScene, Scene newScene) {
        LoadingScreenSwitch();
    }

    void SceneLoaded (Scene newScene, LoadSceneMode sceneMode) {
        _loadingScreen.PlayForward();
    }
}