Android volley unknown constructor -

Android volley unknown constructor -

i trying utilize android volley. here code far:

jsonobjectrequest getrequest = new jsonobjectrequest(request.method.get, url, null, new response.listener<jsonobject>() { @override public void onresponse(jsonobject response) { system.out.println(response); } }, new response.errorlistener() { @override public void onerrorresponse(volleyerror error) { system.out.println(error); } } );

and here imports regarding volley:

import com.android.volley.request; import com.android.volley.requestqueue; import com.android.volley.response; import com.android.volley.volleyerror; import com.android.volley.toolbox.jsonobjectrequest; import com.android.volley.toolbox.volley;

however giving me "cannot resolve constructor" error. ideas?

cast null string

jsonobjectrequest getrequest = new jsonobjectrequest(request.method.get, url, (string)null, new response.listener<jsonobject>() { @override public void onresponse(jsonobject response) { system.out.println(response); } }, new response.errorlistener() { @override public void onerrorresponse(volleyerror error) { system.out.println(error); } } );

android android-volley