JSONArray jsonArray = new JSONArray(json) on a null object reference

Question

Все работало в хостинге 000webhost.com, а когда переехал на fornex.com стал ссылаться на нуль. Ошибка:

java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference

       apply.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            dialog.show();
            data.clear();
            smylocate = msgmy;
            ssendlocate = msgsend;

            downloadJSON("http://z67202.hostde25.fornex.host/stock_service.php");
            listView.setAdapter(adapter);
            adapter.notifyDataSetChanged();




        }
    });




}


private void downloadJSON(final String urlWebService) {

    class DownloadJSON extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }


        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
           // Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
            try {
                loadIntoListView(s);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        @Override
        protected String doInBackground(Void... voids) {
            try {
                URL url = new URL(urlWebService);
                HttpURLConnection con = (HttpURLConnection) url.openConnection();
                StringBuilder sb = new StringBuilder();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
               String json;

                while ((json = bufferedReader.readLine()) != null) {
                    sb.append(json + "\n");
                }
                return sb.toString().trim();
            } catch (Exception e) {
                return null;
            }
        }
    }
    DownloadJSON getJSON = new DownloadJSON();
    getJSON.execute();
}
List<Map<String, String>> data = new ArrayList<Map<String, String>>();

private void loadIntoListView(String json) throws JSONException {
    JSONArray jsonArray = new JSONArray(json);
    String[] stocks = new String[jsonArray.length()];
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject obj = jsonArray.getJSONObject(i);
      //  stocks[i] = "    From:  " +obj.getString("mylocate") + "     To: " + obj.getString("sendlocate") + "      Name: " + obj.getString("starttime")       ;
        String entermylocate=obj.getString("mylocate");
        String entersendlocate=obj.getString("sendlocate");


        if( (entermylocate.contains(smylocate) && entersendlocate.contains(ssendlocate)))
        {
        Map<String, String> datum = new HashMap<String, String>(2);
        datum.put("mylocate", "From: " + entermylocate);
        datum.put("sendlocate","To:   " + entersendlocate);
        datum.put("three fields", "From:  " + obj.getString("starttime") + "    " +
                "Until:  " + obj.getString("endtime")+ "  $=" + obj.getString("money")  );
       // datum.put("Forth Line",obj.getString("endtime"));
        datum.put("id",obj.getString("id"));
        datum.put("name",obj.getString("name"));
        datum.put("email",obj.getString("email"));
            data.add(datum);

        }

    }

    if (data!=null) {


        adapter = new SimpleAdapter(this, data,
                R.layout.list_layout,
                new String[]{"mylocate", "sendlocate", "three fields", "id", "name", "email"},
                new int[]{R.id.txt1, R.id.txt2, R.id.txt3, R.id.txt4, R.id.txt5, R.id.txt6});
        listView.setAdapter(adapter);
        dialog.dismiss();
    }







    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            // selected item
            String selectedid = ((TextView) view.findViewById(R.id.txt4)).getText().toString();
            String selectedmylocate = ((TextView) view.findViewById(R.id.txt1)).getText().toString();
            String selectedsendlocate = ((TextView) view.findViewById(R.id.txt2)).getText().toString();

            String selectedname = ((TextView) view.findViewById(R.id.txt5)).getText().toString();

            String selectedthrii = ((TextView) view.findViewById(R.id.txt3)).getText().toString();

            String selectedemail = ((TextView) view.findViewById(R.id.txt6)).getText().toString();

            Toast toast = Toast.makeText(getApplicationContext(), selectedid, Toast.LENGTH_SHORT);
            toast.show();

            Intent userinfo = new Intent(MainActivity1.this,UserInfo.class);

            userinfo.putExtra("mylocate", selectedmylocate);
            userinfo.putExtra("sendlocate", selectedsendlocate);
            userinfo.putExtra("name", selectedname);
            userinfo.putExtra("three", selectedthrii+"#");

            userinfo.putExtra("email", selectedemail);

            userinfo.putExtra("id", selectedid);

            startActivity(userinfo);




        }
    });




}

Answer 1

Строка, используемая для создания JSONArray, объявлена в методе doInBackground() класса AsyncTask и не видна нигде более. Кроме этого, Вы бы могли использовать sb.toString().trim(); для получения ответа, но этого не произошло. Предлагаю "оглобалить" переменную json. Например, так:

public class MainActivity1 extends Activity {

    String json = "";

    class DownloadJSON extends AsyncTask<Void, Void, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        };

        @Override
        protected String doInBackground(Void... voids) {
            try {
                URL url = new URL(urlWebService);
                HttpURLConnection con = (HttpURLConnection) url.openConnection();
                StringBuilder sb = new StringBuilder();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
                String myVar;
                while ((myVar = bufferedReader.readLine()) != null) {
                    sb.append(myVar + "\n");
                };
                json = sb.toString().trim();
                return json;
            } catch (Exception e) {
                return null;
            };
        };

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
           // Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
            try {
                loadIntoListView(s);
            } catch (JSONException e) {
                e.printStackTrace();
            };
        };
    };

    /*Ваш код здесь*/
    private void downloadJSON(final String urlWebService) {
        DownloadJSON getJSON = new DownloadJSON();
        getJSON.execute();
    };
}

Теперь в AsyncTask общая для всего MainActivity1 переменная json будет получать значение, и именно эта переменная со своим значением будет использоваться для для создания JSONArray.

Answer 2

AndroidManifest.xml

 <application
 android:usesCleartextTraffic="true"

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JSONArray jsonArray = new JSONArray(json) on a null object reference

Ответы (2 шт):