error response with Json request to Disqus on Volley (Android) -

i trying connectt disqus their api

(specifically calling post https://disqus.com/api/oauth/2.0/access_token/ )

i using jsonobjectrequest volley library network calls. response consistently error code 400:

11-19 12:48:17.119: e/volley(16124): [107902] basicnetwork.performrequest: unexpected response code 400 http://disqus.com/api/oauth/2.0/access_token/

i have tried proxy request in charles see more info, , got error message:

and request recorded charles (as can see did add parameter grant_type):

i calling same request in ios version of app, , using same keys , information, , works there. why assume problem somewhere in code, perhaps in way add/encode/not encode parameters... code use send request:

    string url = "http://disqus.com/api/oauth/2.0/access_token/";      jsonobject jsonobj = new jsonobject();     try {         jsonobj.put("grant_type", "authorization_code");         jsonobj.put("client_id", publickey());         jsonobj.put("client_secret", secretkey());         jsonobj.put("redirect_uri", redirecturl());         jsonobj.put("code", code);     } catch (jsonexception e1) {         e1.printstacktrace();     }      jsonobjectrequest jsonobjreq = new jsonobjectrequest(method.post,             url, jsonobj, new response.listener<jsonobject>() {                  @override                 public void onresponse(jsonobject response) {                     try {                         string refreshtoekn = (string) response.get("refresh_token");                         string accesstoekn = (string) response.get("access_token");                          string stam = refreshtoekn+accesstoekn;                     } catch (jsonexception e) {                         e.printstacktrace();                     }                 }             }, new response.errorlistener() {                  @override                 public void onerrorresponse(volleyerror error) {                     volleylog.d("error: " + error.getmessage());                 }             });      volleycontroller.getinstance().addtorequestqueue(jsonobjreq); 

the call falls onerrorresponse

i have tried use stringrequest , add parameters in url no successes

so managed work, love if explain why solution works. basically, instead of using jsonobject , passing jsonobjectrequest used stringrequest , overrode getparams.

was wrong trying send post request jsonobjectrequest?

this entire solution:

string url = "http://disqus.com/api/oauth/2.0/access_token/";     stringrequest stringreq = new stringrequest(method.post,             url, new response.listener<string>() {                 @override                 public void onresponse(string response) {                     string string = response;                 }             }, new response.errorlistener() {                  @override                 public void onerrorresponse(volleyerror error) {                     volleylog.d("error: " + error.getmessage());                 }             }) {         @override         protected map<string,string> getparams(){             map<string,string> params = new hashmap<string, string>();              params.put("grant_type", "authorization_code");             params.put("client_id", publickey());             params.put("client_secret", secretkey());             params.put("redirect_uri",redirecturl());             params.put("code", code);              return params;         }          @override         public map<string, string> getheaders() throws authfailureerror {             map<string,string> params = new hashmap<string, string>();             params.put("content-type","application/x-www-form-urlencoded");             return params;         }     };      volleycontroller.getinstance().addtorequestqueue(stringreq);