How to use Volley library on my Android Studio project?

Right now I have working code for my Android application. I use Volley, but, because of callbacks, I don't feel like my code is as clean as could be. Two functions of my code right now are:

    

        private void updateSettings() {
    ...
        HTTP.requestObject(Request.Method.GET, url, null, new Response.Listener() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    shiftStart = getHour(response.getString("shift_start"));
                    shiftEnd = getHour(response.getString("shift_end"));
                } catch (JSONException e) {
                    Log.i(MainActivity.TAG, "JSON parse error: " + e.toString());
                    e.printStackTrace();
                }

                startCall();
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                HTTP.handleError(error, getApplicationContext());
                startCall();
            }
        }, getApplicationContext());
    ...
}

private void startCall() {
    ...
    CallActivity.makeCall(getApplicationContext());
    ...
}
    

The point here is that I want to make a "call", which isn't very important, but before that I need to update my settings from the server. Of course, I need to make the call after the settings are updated, so I start the call from the Volley callback(I use HTTP.requestObject, which is a custom class that I have made, but it only adds the request to the request queue and sets a timeout). The problem is that when you call the function updateSettings() you don't really expect to start a "call" or anything like that. How can this be avoided?