android_post_volley.java

StringRequest sr = new StringRequest(Request.Method.POST,"http://api.someservice.com/post/comment", new Response.Listener<String>() {
    @Override
    public void onResponse(String response) {
        mPostCommentResponse.requestCompleted();
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        mPostCommentResponse.requestEndedWithError(error);
    }
}){
    @Override
    protected Map<String,String> getParams(){
       //post params
        Map<String,String> params = new HashMap<String, String>();
        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<String, String> getHeaders() throws AuthFailureError {
      //headers params
        Map<String,String> params = new HashMap<String, String>();
        params.put("Content-Type","application/x-www-form-urlencoded");
        return params;
    }
};