Android Volley POST string in body

To send a normal POST request (no JSON) with parameters like username and password, you'd usually override getParams() and pass a Map of parameters:

public void HttpPOSTRequestWithParameters() {    RequestQueue queue = Volley.newRequestQueue(this);    String url = "http://www.somewebsite.com/login.asp";    StringRequest postRequest = new StringRequest(Request.Method.POST, url,         new Response.Listener<String>()         {            @Override            public void onResponse(String response) {                Log.d("Response", response);            }        },         new Response.ErrorListener()         {            @Override            public void onErrorResponse(VolleyError error) {                Log.d("ERROR","error => "+error.toString());            }        }            ) {             // this is the relevant method        @Override        protected Map<String, String> getParams()         {              Map<String, String>  params = new HashMap<String, String>();            params.put("grant_type", "password");             // volley will escape this for you             params.put("randomFieldFilledWithAwkwardCharacters", "{{%stuffToBe Escaped/");            params.put("username", "Alice");              params.put("password", "password123");            return params;        }    };    queue.add(postRequest);}

And to send an arbitary string as POST body data in a Volley StringRequest, you override getBody()

public void HttpPOSTRequestWithArbitaryStringBody() {    RequestQueue queue = Volley.newRequestQueue(this);    String url = "http://www.somewebsite.com/login.asp";    StringRequest postRequest = new StringRequest(Request.Method.POST, url,         new Response.Listener<String>()         {            @Override            public void onResponse(String response) {                Log.d("Response", response);            }        },         new Response.ErrorListener()         {            @Override            public void onErrorResponse(VolleyError error) {                Log.d("ERROR","error => "+error.toString());            }        }            ) {           // this is the relevant method           @Override        public byte[] getBody() throws AuthFailureError {            String httpPostBody="grant_type=password&username=Alice&password=password123";            // usually you'd have a field with some values you'd want to escape, you need to do it yourself if overriding getBody. here's how you do it             try {                httpPostBody=httpPostBody+"&randomFieldFilledWithAwkwardCharacters="+URLEncoder.encode("{{%stuffToBe Escaped/","UTF-8");            } catch (UnsupportedEncodingException exception) {                Log.e("ERROR", "exception", exception);                // return null and don't pass any POST string if you encounter encoding error                return null;            }            return httpPostBody.getBytes();        }    };    queue.add(postRequest);}

As an aside, Volley documentation is non-existent and quality of StackOverflow answers is pretty bad. Can't believe an answer with an example like this wasn't here already.

First thing, I advise you to see exactly what you're sending by either printing to the log or using a network sniffer like wireshark or fiddler.

How about trying to put the params in the body? If you still want a StringRequest you'll need to extend it and override the getBody() method (similarly to JsonObjectRequest)

I know this is old, but I ran into this same problem and there is a much cleaner solution imo found here: How to send a POST request using volley with string body?