getData

.java

private class GetData extends AsyncTask<String, Integer, String> {
    public String convertIsToString(InputStream inputStream)
        throws IOException{
      StringBuilder builder = new StringBuilder();
      BufferedReader reader =
          new BufferedReader(new InputStreamReader(inputStream));
      String line;
      while ((line = reader.readLine()) != null) {
        builder.append(line + "\n");
      }
      if (builder.length() == 0) {
        return null;
      }
      return builder.toString();

    }

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

    protected String doInBackground(String... urlString) {
      HttpURLConnection conn= null;
      InputStream is= null;
      try {
        URL requestURL = new URL(urlString[0]);

        conn = (HttpURLConnection) requestURL.openConnection();
        conn.setReadTimeout(20000 /* milliseconds */);
        conn.setConnectTimeout(25000 /* milliseconds */);
        conn.setRequestMethod("GET");
        conn.setDoInput(true);
        conn.connect();

        int response = conn.getResponseCode();
        if (response != HttpURLConnection.HTTP_OK) {
          return null;
        }
        is = conn.getInputStream();
        String res = convertIsToString(is);
        //close stream
        conn.disconnect();
        if (is != null) {
          is.close();
        }
        //parse data and return
        return res;
      } catch (MalformedURLException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      } finally {

      }
      return null;
    }

    protected void onPostExecute(String result) {
      hideProgressDialog();

      if (StringUtils.isEmpty(result)){
        Toast.makeText(getApplicationContext(), "Empty result", Toast.LENGTH_LONG).show();
        return;
      }
     if (result.contains("|")){
       tvResult.setText(result);
       final String[] mailString = result.split("\n");
       Toast.makeText(getApplicationContext(), "Got "+ mailString.length + "mails from API", Toast.LENGTH_LONG).show();

     } else {
       Toast.makeText(getApplicationContext(), result, Toast.LENGTH_LONG).show();
     }
     final Map<String, Object> map = new HashMap<>();
     map.put(SettingKeys.URL_HOST_NAME, ViewUtils.getTrimmedText(etHostName));
     map.put(SettingKeys.URL_TOKEN, ViewUtils.getTrimmedText(etToken));
     map.put(SettingKeys.URL_AMOUNT, ViewUtils.getTrimmedText(etAmount));
     map.put(SettingKeys.URL_TYPE, ViewUtils.getTrimmedText(etType));
     Utils.checkAndCreateUserSettingsData(getApplicationContext(), new OnSuccessListener() {
       @Override
       public void onSuccess(Object o) {
         Utils.getCurrentUserSettingRef().update(map).addOnCompleteListener(new OnCompleteListener<Void>() {
           @Override
           public void onComplete(@NonNull Task<Void> task) {
             if (task.isSuccessful()){
               Toast.makeText(getApplicationContext(), "Saved link", Toast.LENGTH_SHORT).show();
             } else {
               Toast.makeText(getApplicationContext(), "Can not save link", Toast.LENGTH_SHORT).show();
             }
           }
         });
       }
     });

    }
  }