Volley Helper Class

ApiCaller.java

//In App Module Build.gradle .. import volley dependency as
//   compile 'com.android.volley:volley:1.0.0'
public class ApiCaller {
    public final String TAG = ApiCaller.this.getClass().toString();
    Context networkContext;
    ApiResponseFetcher serverResponse;
   
    //Constructor
    public ApiCaller(ApiResponseFetcher response, Context ctx) {
        this.serverResponse = response;
        this.networkContext = ctx;
    }

public void postDataToServer(int method, String url, final Map<String, String> params) {
       
        RequestQueue queue = Volley.newRequestQueue(networkContext);
        StringRequest request = new StringRequest(method, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                StopProgressBar();
                System.out.println(response);
                if (response != null && response.length() > 0) {
                    try {
                        serverResponse.result(response);
                    } catch (Exception e) {
                        e.printStackTrace();
                        StopProgressBar();
                    }
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
//                Toast.makeText(networkContext, "Error" + error.networkResponse.statusCode, Toast.LENGTH_SHORT).show();
                StopProgressBar();
                Log.d("ERROR", "error => " + error.toString());
                Class app_class = error.getClass();
                if (app_class == AuthFailureError.class) {
                    Log.d("TAG", "AuthFailureError");
                } else if (app_class == com.android.volley.NetworkError.class) {
                    Log.d("TAG", "NetworkError");
                } else if (app_class == NoConnectionError.class) {
                    Log.d("TAG", "NoConnectionError");
                } else if (app_class == com.android.volley.ServerError.class) {
                    Log.d("TAG", "ServerError");
                } else if (app_class == com.android.volley.TimeoutError.class) {
                    Log.d("TAG", "TimeoutError");
                } else if (app_class == ParseError.class) {
                    Log.d("TAG", "ParseError");
                } else if (app_class == VolleyError.class) {
                    Log.d("TAG", "General error");
                }
            }
        }) {
            @Override
            protected Map<String, String> getParams() {
                return params;
            }

            //
            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> params = new HashMap<>();
                params.put("Content-Type", "application/x-www-form-urlencoded");
                return params;
            }
        };
        request.setShouldCache(false);
        request.setRetryPolicy(new DefaultRetryPolicy(50 * 1000, 1, 1.0f));
        queue.add(request);
    }
}

ApiResponseFetcher.java

public interface ApiResponseFetcher<T> {
    public void result(String resp);

MainActivity.java

Use:In Yor Activity Class

ApiCaller caller=new ApiCaller(this, context);
 Map<String, String> params=new HashMap<>();
params.add("key","value");
caller.postDataToServer(Request.Method.POST,"Your_website_url",params);

Implement ApiResponseFetcher in Your Activity, It overrides result method

@Override
public void result(String resp)
{
//Parse your response here 
}