Android: Volley String request onresponse is not called

Question

I am trying to send data from android to php using POST method

the php part is tested alone and it's 100% working and it returns a json string as supposed

the android part isn't working it doesn't print error or even the required response

Here is the code and it's tested , printing a string "test" using Toast , but it doesn't change in the volley code :(

this is the php code:

<?php
    require_once(__DIR__.'/../dbConnect.php');  


    $userName=$_POST['username']; 

    $query = "SELECT * FROM users WHERE username='$userName'";
    $result = pg_query($con, $query);
    $rows = pg_num_rows($result);

    while ($row = pg_fetch_row($result)) 
    {
        $field = pg_num_fields( $result );

        for ( $i = 0; $i < $field; $i++ ) {

            $name = pg_field_name( $result, $i );
            $user_arr[$name] = $row[$i]; 
        }               
    }

    echo json_encode($user_arr);

    pg_close($con); 

    ?>

and this is android code:

initializing the test string to display output

String test = "none";

this is where I call the method

  setUserData(username);
  Toast.makeText(LoginActivity.this, test, Toast.LENGTH_SHORT).show();

and this is the method:

  private void setUserData(final String username)
    {
        StringRequest strReq = new StringRequest(Request.Method.POST,
                Server.GET_USERDATA_URL, new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {

                   test= "test = "+response;

            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError volleyError) {
                Toast.makeText(LoginActivity.this, volleyError.getMessage().toString(), Toast.LENGTH_LONG).show();

            }
        })

        {

            @Override
            protected Map<String, String> getParams() {
                // Posting parameters to getData url
                Map<String, String> params = new HashMap<String, String>();
                params.put(Server.KEY_USERNAME, username);
                return params;
            }

        };
        //Creating a Request Queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        //Adding request to the queue
        requestQueue.add(strReq);
    }

Answer 1

Check if u have taken internet permission .

Also add toast in

onResponse()
 Toast.makeText(LoginActivity.this, response.toString(), Toast.LENGTH_LONG).show(); 

Answer 2

You have a concurrency issue. When you execute your setUserData(username) method Volley is doing the work on a background thread. Therefore you need to wait for the response before you can display it in a Toast. At the moment when you call:

Toast.makeText(LoginActivity.this, test, Toast.LENGTH_SHORT).show();

The server still hasn't responded and test will still be none. You need to call the toast from the onResponse callback:

private void setUserData(final String username) {

    StringRequest strReq = new StringRequest(
        Request.Method.POST,
        Server.GET_USERDATA_URL, 
        new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {

                test = "test = "+response;
                showToast();

            }
        }, 
        new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError volleyError) {
                Toast.makeText(LoginActivity.this, volleyError.getMessage().toString(), Toast.LENGTH_LONG).show();

        }
    })

    {

        @Override
        protected Map<String, String> getParams() {
            // Posting parameters to getData url
            Map<String, String> params = new HashMap<String, String>();
            params.put(Server.KEY_USERNAME, username);
            return params;
        }

    };
    //Creating a Request Queue
    RequestQueue requestQueue = Volley.newRequestQueue(this);
    //Adding request to the queue
    requestQueue.add(strReq);
}

private void showToast() {

    Toast.makeText(LoginActivity.this, test, Toast.LENGTH_SHORT).show();
}