IEnumerator Start () {
string str = "file://" + Application.streamingAssetsPath+ "/a.txt";
WWW www = new WWW(str);
yield return www;
if (www.isDone)
{
GetComponent<GUIText>().text=www.text;
}
}
原文：http://www.cnblogs.com/Feiyuzhu/p/4955907.html