Application.streamingAssetsPath Android平台上不能用File直接讀取，必須通過WWW

// Application.streamingAssetsPath 獲取StreamingAssets文件夾的物理路徑

IEnumerator Start()
    {
       string Url ="file://"+Application.streamingAssetsPath + "/1.jpg";
        WWW www = new WWW(Url);
        yield return www;
        if (www.error != null)
            Debug.Log(www.error.ToString()+"...ERROR");
        Texture2D t2d = www.texture;
        gameObject.renderer.material.mainTexture = t2d;
       // Debug.Log(Url);
    }