JSON file empty when i open it with app json viewer

with my code, when i open a JSON file with app for smartphone JSON VIEWER, file is empty...i not see content...why?

Now,i show you my code how i save file json....

Thanks in advance everybody!

public String showResult(View v) throws IOException {
String  result = "";

        JsonObject json = new JsonObject();
        for (Planet p : plAdapter.getBox()) {
            if (p.isSelected()){
                json.put("name",p.getName());
                json.put("distance",p.getDistance());
                json.put("quantity",p.getQuantità());

            }
        }
         result=json.toString();

        String path = Environment.getExternalStorageDirectory()
                .getAbsolutePath() + "/droidText/";

        //FileWriter file=null;

    /*  try {
            file = new FileWriter(path+"filename5.json");
            file.write(result);


        }catch(IOException ie){}
        finally{


            file.flush();
            file.close();
        }*/
        FileWriter file = new FileWriter(path+"filename31.json");
            file.write(result);
            file.close();
            System.out.println("Successfully wrote Json result to file.");
        /*catch(IOException r){

        }*/
        System.out.println(result);
        return result;

    } 

JsonObject class:

private static class JsonObject {
        public void put(String name, String name1) {
        }
    }