Vector3 screenPos = Camera.main.WorldToScreenPoint(m_target.position); //得到主相机屏幕坐标
Vector2 position;
RectTransformUtility.ScreenPointToLocalPointInRectangle(GameObject.Find("Canvas").GetComponent<RectTransform>(),screenPos,m_uiCamera, out position); //param1 UI canvas param2 UI相机 param3 输出坐标
GetComponent<RectTransform>().anchoredPosition = position;
