把要实例化的物体放入Resources文件夹内，然后使用
Resources.Load()方法
GameObject go = Resources.Load("DialogUI") as GameObject;
GameObject gameObject = Instantiate(go, Vector3.zero, Quaternion.identity) as GameObject;
Transform transform = gameObject.transform.GetChild(3).GetChild(0);
Text text = transform.GetComponent<Text>();
text.text = "ETAGame";