IEnumerator DragNach(float _target, float _time)
    {
        float _t = 0f;
        while (_t<1)
        {
            _t += Time.deltaTime/_time;
            sr.horizontalNormalizedPosition = Mathf.Lerp(sr.horizontalNormalizedPosition,_target,_t);
            yield return null;
        }
        if (_target <= 0.1) transform.GetChild(2).SetAsFirstSibling(); else if (_target >= 0.9) transform.GetChild(0).SetAsLastSibling();
        sr.horizontalNormalizedPosition = .5f;
    }
    public void OnEndDragging()
    {

        StartCoroutine(DragNach(Mathf.Round(sr.horizontalNormalizedPosition * 2f) * .5f, .2f));
    }