public class LoginActivity extends BaseActivity implements VolleyTasksListener {

private EditText edtUser;
private EditText edtPassword;
private Button btnLogin;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    findViews();
}

private void callLoginService() {

    if (ConnectionUtils.isConnectedNetwork(this)) {
        if (!edtUser.getText().toString().equals("")) {
            if (!edtPassword.getText().toString().equals("")) {

                JSONObject jsonMainObject = new JSONObject();
                try {
                    jsonMainObject.put("username", edtUser.getText().toString());
                    jsonMainObject.put("password", edtPassword.getText().toString());
                    VolleyTasks.makeVolleyPost(LoginActivity.this, Constant.LOGIN_URL, jsonMainObject, "Login");

                } catch (JSONException e) {
                    e.printStackTrace();
                }
            } else {
                DialogUtils.showPositiveDialog(this, "", "Please enter valid Password");

            }
        } else {
            DialogUtils.showPositiveDialog(this, "", "Please enter valid UserId ");
        }
    } else {
        DialogUtils.showPositiveDialog(this, "", getString(R.string.error_connection));
    }
}

private void findViews() {
    edtUser = (EditText) findViewById(R.id.edt_user_id);
    edtPassword = (EditText) findViewById(R.id.edt_password);
    btnLogin = (Button) findViewById(R.id.btn_login);

    btnLogin.setOnClickListener(this);
}

@Override
public void onClick(View v) {
    super.onClick(v);

    switch (v.getId()) {
        case R.id.btn_login:
            callLoginService();
            break;
    }

}

@Override
public void handleError(Exception error) {

    L.d("error" + error);}

@Override
public void handleResult(String method_name, JSONObject response) {

    L.d("response" + response);
    if (response != null) {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.serializeNulls();
        Gson gson = gsonBuilder.create();
        if (method_name.equals("Login")) {
            AbstractLogin abstractLogin = gson.fromJson(response.toString(), AbstractLogin.class);
            if (abstractLogin != null) {
                if (abstractLogin.getApi().equals("UserLogin")) {

                    Intent intent = new Intent(LoginActivity.this, HomeActivity.class);
                    startActivity(intent);
                    finish();
                } else {
                    DialogUtils.showPositiveDialog(this, "", getString(R.string.err_msg_request_failed));
                }
            }
        }
    }
}}

public class VolleyTasks {


static VolleyTasksListener volley;
private static String TAG = VolleyTasks.class.getSimpleName();
private static Context mContext;

public static void makeVolleyPost(Fragment context, String url, final JSONObject postdata, String method_name) {
    mContext = ((Activity) context.getActivity());
    volley = (VolleyTasksListener) context;
    startVollyTask(url, postdata, method_name);
}

public static void makeVolleyPost(final Activity context, String url, final JSONObject postdata, String method_name) {
    mContext = context;
    volley = (VolleyTasksListener) context;
    startVollyTask(url, postdata, method_name);
}

private static void startVollyTask(String url, final JSONObject postdata, final String method_name) {
    JsonObjectRequest jsonObjReq = new JsonObjectRequest (Request.Method.POST,
            url, postdata, new Response.Listener<JSONObject>() {

        @Override
        public void onResponse(JSONObject response) {
            L.d(response.toString());
            if (response != null) {

                volley.handleResult(method_name, response);

            }
        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d (TAG, "Error: " + error.getMessage ());

            volley.handleError(error);
        }
    });

    // Adding request to request queue
    ImarqApplication.getInstance ().addToRequestQueue (jsonObjReq);

    L.i(url);
    L.i(postdata.toString());
}

public static void makeVolleyGETObject(final Activity context, String url, final String method_name) {
    volley = (VolleyTasksListener) context;
    JsonObjectRequest jsonObjReq = new JsonObjectRequest (Request.Method.GET,
            url, null, new Response.Listener<JSONObject>() {

        @Override
        public void onResponse(JSONObject response) {
            L.d(response.toString());



            volley.handleResult(method_name, response);
        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d (TAG, "Error: " + error.getMessage ());
            L.ToastMessage(context, "Sorry for the inconvenience. Please try again.");
        }
    });

    // Adding request to request queue
    ImarqApplication.getInstance().addToRequestQueue(jsonObjReq);
}

public static void makeVolleyGETObject(final Fragment context, String url, final String method_name) {
    volley = (VolleyTasksListener) context;

    JsonObjectRequest jsonObjReq = new JsonObjectRequest (Request.Method.GET,
            url, null, new Response.Listener<JSONObject>() {

        @Override
        public void onResponse(JSONObject response) {
            L.d(response.toString());

            volley.handleResult(method_name, response);
        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d (TAG, "Error: " + error.getMessage ());
            Toast.makeText(context.getActivity(), error.getMessage(), Toast.LENGTH_SHORT).show();
            // hide the progress dialog
        }
    });

    // Adding request to request queue
    ImarqApplication.getInstance().addToRequestQueue(jsonObjReq);
}}