Android create a Json String

JSONObject jArrayFacebookData = new JSONObject();    JSONObject jObjectType = new JSONObject();    // put elements into the object as a key-value pair    jObjectType.put("type", "facebook_login");    jArrayFacebookData.put("system", jObjectType);    // 2nd array for user information    JSONObject jObjectData = new JSONObject();    // Create Json Object using Facebook Data    jObjectData.put("facebook_user_id", id);    jObjectData.put("first_name", first_name);    jObjectData.put("last_name", last_name);    jObjectData.put("email", email);    jObjectData.put("username", username);    jObjectData.put("birthday", birthday);    jObjectData.put("gender", gender);    jObjectData.put("location", place);    jObjectData.put("display_photo", display_photo_url);    jArrayFacebookData.put("data", jObjectData);

this will give you jsonObject, but not array, i don't see any point in using JSONArray. JSONObject is better in this case. you will see following output as String

{   "system":{      "type":"facebook_login"   },   "data":{      "birthday":"06\/22\/1986",      "first_name":"Harsha",      "username":"harshamv",      "location":"Bangalore, India",      "email":"hmv2206@gmail.com",      "last_name":"Mv",      "gender":"male",      "facebook_user_id":"1423671254",      "display_photo":"http:\/\/graph.facebook.com\/1423671254\/picture?type=large"   }}

Create JSON objects for the jArrayFacebookData (not JSONArray as you have taken) and put jObjectType and jObjectData inside it.

Check this JSONObject put object method.

Update:

Your JSON is having error:

Valid JSON is:

{    "system": {        "type": "facebook_login"    },    "data": {        "birthday": "06/22/1986",        "first_name": "Harsha",        "username": "harshamv",        "location": "Bangalore, India",        "email": "hmv2206@gmail.com",        "last_name": "Mv",        "gender": "male",        "facebook_user_id": "1423671254",        "display_photo": "http://graph.facebook.com/1423671254/picture?type=large"    }}

Final Solution:

     try        {    JSONObject jArrayFacebookData = new JSONObject();        JSONObject jObjectType = new JSONObject();        jObjectType.put("type", "facebook_login");        JSONObject jObjectData = new JSONObject();        jObjectData.put("facebook_user_id", "2323");        jObjectData.put("first_name", "2323");        jObjectData.put("last_name", "2323");        //put other data here       jArrayFacebookData.put("system", jObjectType);    jArrayFacebookData.put("data",jObjectData);    System.out.println("==========> Final output => "+jArrayFacebookData.toString());  }  catch(Exception e)  {  }

how i post json string.

for(int i=0; i<iArr.size(); i++){    if(i==0){        st = "{\"userId\":" + iArr.get(i) + "}";        str += st;    }else if(i>0 && i<iArr.size()-1){        st = ",{\"userId\":" + iArr.get(i) + "}";        str+=st;    }else if(i==iArr.size()){        st = ",{\"userId\":" + iArr.get(i) + "}]}";        str+=st;    }}String myPost = "{\"project\":{\"Name\":"+ "\""+ title + "\""              + ",\"Description\":" + "\""+ desc + "\""              + ",\"createdBy\":" + usrid + ""              + ",\"startDate\":" + "\""+ startdate + "\""              + ",\"dueDate\":" + "\""+ duedate + "\""              + ",\"projectLeadId\":" + leadPosition + ""              + ",\"QAId\":" + QAssurencePosition + ""              + ",\"TotalHour\":" +"\""+ edtHour + "\""+ "},\"members\":[";                myPost += str;                myPost +="]}";                RequestPackage myPackage = new RequestPackage();                myPackage.setUri(getaddProject);                myPackage.setMethod("POST");                myPackage.setParam("My Post",myPost+"");                new MyTask().execute(myPackage);                Toast.makeText(CreateProject.this,"Testing String: " + myPost,Toast.LENGTH_LONG ).show();                Log.d("My Post :",myPost); }