if($_SERVER['REQUEST_METHOD'] == 'POST') {
    $data = file_get_contents("php://input");
    echo $data;
}
echo 'OK'

if($_SERVER['REQUEST_METHOD'] == 'POST') {
    $data = file_get_contents("php://input");
    echo $data;
}
echo 'OK'

echo $data;

String MY_SITE = "http://192.168.1.37/index.php"; // Пока тут адрес локального сервера
                URL url =new URL(MY_SITE); 
                HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();

                urlConnection.setRequestProperty("Content-Type", "application/json");
                urlConnection.setRequestMethod("POST");
                urlConnection.setDoInput(true);
                urlConnection.setDoOutput(true);
                
                Log.d("myLogs", "___" + jsonObj.toString()); <-ЭТО ПОСЛЕДНЯЯ СТРОКА В ЛОГЕ

                BufferedOutputStream bos = new BufferedOutputStream(urlConnection.getOutputStream());
                Log.d("myLogs", "qqq");
                bos.write(jsonObj.toString().getBytes());

if($_SERVER['REQUEST_METHOD'] == 'POST') {
    $data = file_get_contents("php://input");
    echo 'data:{'.json_encode($data).'}';
}

    class RequestTask extends AsyncTask<Void, Void, Void> {

        //private BufferedOutputStream bos;
        JSONObject jsonObj;

        @Override
        protected Void doInBackground(Void... params) {

            Log.d("myLogs","doInBackground");
            // Формируем jsonObject из файла
            try {

                File yourFile = new File(Environment.getExternalStorageDirectory(), "/MyFiles/fileSD1.txt");
                FileInputStream stream = new FileInputStream(yourFile);
                String jsonStr = null;
                try {
                    FileChannel fc = stream.getChannel();
                    MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());

                    jsonStr = Charset.defaultCharset().decode(bb).toString();
                }
                finally {
                    stream.close();
                }

                jsonObj = new JSONObject(jsonStr);

                Log.d("myLogs",jsonObj.toString());

                // Отправка json, отправку делаем в AsyncTask


            }
            catch (Exception e) {
                e.printStackTrace();
            }

            // Отправка данных
            try {

                String MY_SITE = "http://192.168.1.37/index.php"; // Пока тут адрес локального сервера
                URL url =new URL(MY_SITE); // пример "http://ru.stackoverflow.com/"
                HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();

                urlConnection.setRequestProperty("Content-Type", "application/json");
                urlConnection.setRequestMethod("POST");
                urlConnection.setConnectTimeout(5000);
                urlConnection.setDoInput(true);
                urlConnection.setDoOutput(true);

                Log.d("myLogs", "___" + jsonObj.toString());
                BufferedOutputStream bos = new BufferedOutputStream(urlConnection.getOutputStream());
                Log.d("myLogs", "qqq");
                bos.write(jsonObj.toString().getBytes());
                bos.flush();
                bos.close();

                Log.d("myLogs", "отправили данные");
                if (urlConnection.getResponseCode()==HttpURLConnection.HTTP_OK) {
                    String result = urlConnection.getResponseMessage();
                    Log.d("myLogs", "server response: " + result); //проверить, что вернет сервер, сервер должен вернуть тестовую строку

                    BufferedReader reader = new BufferedReader(
                            new InputStreamReader(urlConnection.getInputStream()));

                    StringBuffer sb = new StringBuffer(1024);
                    String tmp="";
                    while((tmp=reader.readLine())!=null)
                        sb.append(tmp).append("\n");
                    reader.close();

                    Log.d("myLogs",sb.toString());

                }
                else {
                    Log.d("myLogs","no");
                }

            } catch (Exception e) {
                //System.out.println("Exp=" + e);
                e.printStackTrace();

            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {

             super.onPostExecute(result);
        }

        @Override
        protected void onPreExecute() {

            super.onPreExecute();
        }
    }

if($_SERVER['REQUEST_METHOD'] == 'POST') {
	$data = file_get_contents('php://input');
	
		//Запись полученных данных в файл
  $file = fopen ("file.txt","r+");
  //$str = "Hello, world!";
  if ( !$file )
  {
    echo("Ошибка открытия файла");
  }
  else
  {
    fputs ( $file, $data);
  }
  fclose ($file);
	
	echo '{data:'.$data.'}';
}