用Volley-nullpointerexception

1  public Request(int method, String url, Response.ErrorListener listener) {
2         mMethod = method;
3         mUrl = url;
4         mErrorListener = listener;
5         setRetryPolicy(new DefaultRetryPolicy());
6 
7         mDefaultTrafficStatsTag = TextUtils.isEmpty(url) ? 0: Uri.parse(url).getHost().hashCode();
8    }