Sample code

SomeFragment.java

public class HomeFragment extends Fragment {
  
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";
    private String mParam1;
    private String mParam2;
    private OnFragmentInteractionListener mListener;

    private String urlCitiesObj = "url";
    private static String TAG = HomeFragment.class.getSimpleName();
    private TextView txtResponse;
    private String jsonResponse;
    // private Context globalContext = null;
    // private Context globalContext = getActivity().getApplicationContext(); // don't need this.

    public static HomeFragment newInstance(String param1, String param2) {
        HomeFragment fragment = new HomeFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    public HomeFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    
    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View layout = inflater.inflate(R.layout.fragment_home, container, false);
        // makeJsonArrayRequest(); // NOTE: don't call any request before your UI is fully initialized
        txtResponse = (TextView) layout.findViewById(R.id.txtResponse);
        return layout;
    }

    private Activity mActivity;

    @Override
    public void onAttach(Activity activity) {
      if (activity instanceOf OnFragmentInteractionListener)
        mListener = (OnFragmentInteractionListener) activity; // this is how your get your callback
    }

    @Override
    public void onActivityCreated(Bundle something) {
      super.onActivityCreated(something);
      // call your request here
      makeJsonArrayRequest();
    }
    
    private void makeJsonArrayRequest() {
        JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
                urlCitiesObj, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.d(TAG, response.toString());
                try {
                    JSONArray jsonArray = response.getJSONArray("GetCitiesResult");
                    for (int i = 0; i < jsonArray .length(); i++) {

                        JSONObject jSONObject = jsonArray .getJSONObject(i);
                        String cityID = jSONObject .getString("CityID");
                        String cityName = jSONObject .getString("CityName");

                        jsonResponse += "CityID: " + cityID  + "\n\n";
                        jsonResponse += "CityName: " + cityName  + "\n\n";

                        txtResponse.setText(jsonResponse);
                    }

                    // this make no sense
                    // if( isAdded()){
                    //    getActivity().getApplicationContext();
                    // }
                } catch (JSONException e) {
                    e.printStackTrace();
                    if (isAdded()) {
                      getActivity().runOnUIThread(new Runnable() {
                        @Override
                        public void run() {
                          Toast.makeText(getActivity(), "Error: " + e.getMessage(), Toast.LENGTH_LONG).show();
                        }  
                      }
                    }
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(TAG, "Error: " + error.getMessage());
                if (isAdded()) {
                  getActivity().runOnUIThread(new Runnable() {
                    @Override
                    public void run() {
                      Toast.makeText(getActivity(), "Error: " + error.getMessage(), Toast.LENGTH_LONG).show();
                    }  
                  }
                }
            }
        });

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

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        public void onFragmentInteraction(Uri uri);
    }
}