为了考虑切换场景的情况，所以还得有一个跳转场景的管理器。本来就算跟ViewManager无关，如果要做一个跳转场景的过场动画，那么应该也是要有这么一个SceneLoadManager的。切场景的时候先把过场动画加载进来，注意这个过场动画得是Don't Destroy的。然后开始异步加载场景，场景加载完成过后在退出过场动画。然后还可以执行一个回调函数，例如打开一个界面。

public class SceneLoadManager : MonoBehaviour {
    public static SceneLoadManager Instance { get; private set; }
    private AsyncOperation AsyncOpe;
    void Awake()
    {
        Instance = this;
    }
    public void LoadSceneAsync(string sceneName, Action callBack)
    {
        ShowLoadingAnim();
        StartCoroutine(LoadAsync(sceneName, callBack));
    }
    public void LoadSceneAsync(int sceneIndex,Action callBack)
    {
        ShowLoadingAnim();
        StartCoroutine(LoadAsync(sceneIndex, callBack));
    }
    IEnumerator LoadAsync(string sceneName,Action callBack)
    {
        AsyncOpe = SceneManager.LoadSceneAsync(sceneName);
        yield return AsyncOpe;
        if(AsyncOpe.isDone)
        {
            OutLoadingAnim();
            callBack();
            AsyncOpe = null;
        }
    }
    IEnumerator LoadAsync(int sceneIndex,Action callBack)
    {
        AsyncOpe = SceneManager.LoadSceneAsync(sceneIndex);
        yield return AsyncOpe;
        if(AsyncOpe.isDone)
        {
            OutLoadingAnim();
            callBack();
            AsyncOpe = null;
        }
    }
    void ShowLoadingAnim()
    {
        //if (LoadingHandler.Instance!=null)
        //    LoadingHandler.Instance.Show();
    }
    void OutLoadingAnim()
    {
        //if (LoadingHandler.Instance!=null)
        //    LoadingHandler.Instance.Out();
    }
    public float getProgress()
    {
        return AsyncOpe.progress;
    }
}