sonObjectRequest actuallyaccepts JSONObject as body.

From http://arnab.ch/blog/2013/08/asynchronous-http-requests-in-android-using-volley/

final String url = "some/url";final JSONObject jsonBody = /* ... */;new JsonObjectRequest(url, jsonBody, new Response.Listener<JSONObject>() { ... });

Here is the offical code and javadoc (@param jsonRequest):

/** * Creates a new request. * @param method the HTTP method to use * @param url URL to fetch the JSON from * @param jsonRequest A {@link JSONObject} to post with the request. Null is allowed and *   indicates no parameters will be posted along with request. * @param listener Listener to receive the JSON response * @param errorListener Error listener, or null to ignore errors. */public JsonObjectRequest(int method, String url, JSONObject jsonRequest,        Listener<JSONObject> listener, ErrorListener errorListener) {    super(method, url, (jsonRequest == null) ? null : jsonRequest.toString(), listener,                errorListener);}