Android Converting String to JSON

Question

I need advice into how to work out a method in Android which has to pick a string loaded with JSON data and then convert it back to JSON.

For the time being, I have programmed the following but I'm not sure if I'm on the right track or not.

private void convert_JSON()
    {
    String json;
    //funcions per a cridar el string amb JSON i convertir-lo de nou a JSON
    JSONArray jsas = new JSONArray(); 
    for (int i =0; i < jsas.length(); i++)
    {
        JSONObject message = jsas.getJSONObject(i);
        String content = message.getString("content");
    }

    }

The JSON is loaded into a String in this other method:

private void read_JSON(String json)
    {

        JSONObject jObject = new JSONObject(json);
        JSONArray jso3 = new JSONArray (jObject.getString("Nombres_Hijos"));
        String name = jso3.getString("Nombre");
        System.out.println(name);

        String surname = jso3.getString("Apellidos");
        System.out.println(surname);

        int date = jso3.getInt("Año_nacimiento");
        System.out.println(date);

        JSONArray jsa2 = jso3.getJSONArray ("Nombres_Hijos");
        String names = jsa2.toString();
        for (int i=0; i < jsa2.length(); i++)
        {
            System.out.println(jsa2.getString(i));  
        }
        jso3.toString(json);
    }

And, lastly, the JSON is created within the MainActivity.java, not as a split file yet that does work correctly:

private void create_JSON(String json)
    {
        JSONObject jso = new JSONObject();

        try {
            jso.put("Nombre","Miguel");
            jso.put("Apellidos", "Garcia");
            jso.put("Año_nacimiento", 1990);
            JSONArray jsa = new JSONArray();
            jsa.put("Blur");
            jsa.put("Clur");
            jso.put("Nombres_Hijos", jsa);

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return jso.toString();

In short: what I want to know is if my method convert_JSON is on the right track or I'm misunderstanding how it's supposed to work like.

Thank you very much for your help.

Yours sincerely,

Mauro.

Have you read this? http://stackoverflow.com/questions/9605913/how-to-parse-json-in-android — brandonscript, Dec 19 '13 at 17:56

Entreco · Answer 1 · 2013-12-19T15:28:05.693

13

You can convert a jsonstring back to json using the following JSONObject(String json) constructor:

JSONObject jsonObject = new JSONObject(jsonString);

Just, put it inside a try catch block and you should be good to go :)

edited Dec 19 '13 at 15:28

answered Dec 19 '13 at 15:21

Entreco

12,738
8
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score 6 · Answer 2 · edited Mar 21 '23 at 07:03

You can create a JSONObject from a String using the constructor:

JSONObject json = new JSONObject(myString);

And to convert your JSONObject to a String, just use the toString() method:

String myString = json.toString();

Additionally, if you are trying to get a specific String value from the JSONObject, you can do this:

if (json.has("content"))
{
    String content = json.getString("content");
    //do something with content string
}

Finally, if you aren't very comfortable using JSONObject, I recommend using the tools provided by my droidQuery library to help you parse, such as:

Object[] array = $.toArray(myJSONArray);

and

Map<String, ?> map = $.map(myJSONObject);

score -1 · Answer 3 · answered Dec 19 '13 at 15:20

-1

If you want a pure copy/paste example have a look here Alternatively I would suggest using one of the many well documented libraries. My personal favourite is GSON

Plenty of examples on the net on how to use this.

answered Dec 19 '13 at 15:20

Husman

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Android Converting String to JSON

3 Answers3