volley 发送post请求

public static void postNewComment(Context context,final UserAccount userAccount,final String comment,final int blogId,final int postId){
    mPostCommentResponse.requestStarted();
    RequestQueue queue = Volley.newRequestQueue(context);
    StringRequest sr = new StringRequest(Request.Method.POST,"http://api.someservice.com/post/comment", new Response.Listener() {
        @Override
        public void onResponse(String response) {
            mPostCommentResponse.requestCompleted();
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            mPostCommentResponse.requestEndedWithError(error);
        }
    }){
        @Override
        protected Map getParams(){
            Map params = new HashMap();
            params.put("user",userAccount.getUsername());
            params.put("pass",userAccount.getPassword());
            params.put("comment", Uri.encode(comment));
            params.put("comment_post_ID",String.valueOf(postId));
            params.put("blogId",String.valueOf(blogId));
 
            return params;
        }
 
        @Override
        public Map getHeaders() throws AuthFailureError {
            Map params = new HashMap();
            params.put("Content-Type","application/x-www-form-urlencoded");
            return params;
        }
    };
    queue.add(sr);
}
 
public interface PostCommentResponseListener {
    public void requestStarted();
    public void requestCompleted();
    public void requestEndedWithError(VolleyError error);
}