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Parsing arrays in Json using Gson

Parsing arrays in json using Gson.
I have this following json and trying to parse it.
{
"success": true,
"message": "success message",
"data": [
{
"city": "cityname",
"state": "statename",
"pin": 0,
"name" :{
"firstname" : "user"
},
"id" :"emailid"
}],
"status" : "done"
}
So, I have created pojo classes using http://www.jsonschema2pojo.org/
Now, I want to parse the array, for value "city".This is how I did but not sure what is wrong here.
Gson gson = new Gson();
Records obj = gson.fromJson(response,Records.class);
try {
JSONArray jsonArray = new JSONArray(obj.getData());
for(int i=0; i<jsonArray.length(); i++)
{
JSONObject object = jsonArray.getJSONObject(i);
String city = object.getString("city");
AlertDialog.Builder dialog = new AlertDialog.Builder(this);
dialog.setMessage(city);
dialog.show();
}}
catch (Exception e) {
e.printStackTrace();
}
And this is what getData() is defined in model class:
public class Records {
//////
private ArrayList<Datum> data = null;
public ArrayList<Datum> getData() {
return data;
}

this is not required:
try {
JSONArray jsonArray = new JSONArray(obj.getData());
...
}
catch
...
you just need to do
Records obj = gson.fromJson(response,Records.class);
and then
obj.getData();
would be great if you check that getData() is not null, beacuse something xould go wrong when deserialising
for getting the city: use the getter in the Datum class, you have at the end a list of those obejcts when you call getData
public String getCity() {
return city;
}

I am getting HTTP response string like below. I want subject_id and status string from response string

Response string is like this:
{
"images": [
{
"transaction": {
"status": "success",
"topLeftX": 325,
"topLeftY": 451,
"gallery_name": "Ironman",
"subject_id": "Tony",
"confidence": 0.99414,
"height": 630,
"width": 630,
"face_id": 1,
"quality": 1.75477
},
"candidates": [
{
"subject_id": "Tony",
"confidence": 0.99414,
"enrollment_timestamp": "1487644861022"
},
{
"subject_id": "Tony",
"confidence": 0.99414,
"enrollment_timestamp": "1487644876280"
}
]
}
]
}
I tried this code but not working..
JSONArray arr = new JSONArray(response);
JSONObject jObj = arr.getJSONObject(0);
String status = jObj.getString("status");
String message = jObj.getString("subject_id");

Use json simple lib
JSONObject json = new JSONObject(yourString);
JSONArray images = json.getJSONArray("images");
and you can loop throw this array
for (int i = 0; i < images.length(); i++) {
JSONObject o = images.getJSONObject(i);
....
}

You can use GSON to parse JSON Strings. If you just want the first object of the images array you can use this code:
JsonParser jsonParser = new JsonParser();
JsonObject obj = jsonParser.parse(responseString).getAsJsonObject();
JsonArray images = obj.getAsJsonArray("images");
String subjectId = images.get(0).getAsJsonObject().get("transaction")
.getAsJsonObject().get("subject_id").getAsString();

You can create pojo class for response
Also you can use GSON library for get response string.

use this
#Override
protected void onPostExecute(String result) {
JSONObject jsonobj;
// TODO Auto-generated method stub
super.onPostExecute(result);
if (result != null) {
if (result.equals("failure")) {
Toast.makeText(context, "Check your Username or Password", Toast.LENGTH_LONG).show();
dialog.dismiss();
} else {//ths is getting data for vehicl_list_unread_count code, client id,restapi_key
try {
Log.d(TAG, "onPostExecute: this inner of post" + getcontent_for_validate);
jsonobj = new JSONObject(getcontent_for_validate);
System.out.println("this is get content" + jsonobj.toString()); JSONArray array = jsonobj.getJSONArray("images");for (int i = 0; i < array.length(); i++) {
JSONArray transaction = array.getJSONObject(i).getJSONArray("transaction");for (int i = 0; i < array.length(); i++)
String status = transaction.getJSONObject(i).getString("status");
Password = editText_password.getText().toString();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
} else {
dialog.dismiss();
Toast.makeText(context, "Check net connection", Toast.LENGTH_LONG).show();
}
}

You tried
JSONArray arr = new JSONArray(response);
but you should
JSONObject arr = new JSONObject(response);
Because your main json is json object, not JSONArray

How to access nested elements of JSON data in Java?

I'm getting JSON data from a url and I want to show the data on my website. I am successfully showing all JSON data except JSON Hierarchy (JSON Object) data. I am able to access JSONArray person and error data. But, I am not able to access hierarchy (JSON Object) updated data.
I want to access updated.time.
import java.io.IOException;
import java.net.URL;
import org.apache.commons.io.IOUtils;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;
public class ParseJson1 {
public static void main(String[] args) {
String url = "http://freemusicarchive.org/api/get/genres.json?api_key=60BLHNQCAOUFPIBZ&limit=2";
/*
{
"person": [
{
"name": "John",
"city": "Mumbai"
},
{
"name": "Rahul",
"city": "Delhi"
},
{
"name": "Sanjana",
"city": "Amritsar"
},
{
"name": "Anjali",
"city": "Hyderabad"
},
{
"name": "Mukund",
"city": "Bangalore"
},
{
"name": "Raunak",
"city": "Patna"
}
],
"updated": {
"time": "14:17:48",
"date": "2016-04-10"
},
"error": "2353"
}
*/
try {
String genreJson = IOUtils.toString(new URL(url));
JSONObject genreJsonObject = (JSONObject) JSONValue.parseWithException(genreJson);
// get the error
System.out.println(genreJsonObject.get("error"));
//Get Array Values
JSONArray genreArray = (JSONArray) genreJsonObject.get("person");
// get the first genre
JSONObject firstGenre = (JSONObject) genreArray.get(0);
System.out.println(firstGenre.get("name"));
// get the Second
JSONObject firstGenre = (JSONObject) genreArray.get(1);
System.out.println(firstGenre.get("name"));
// get the third
JSONObject firstGenre = (JSONObject) genreArray.get(2);
System.out.println(firstGenre.get("city"));
} catch (IOException | ParseException e) {
e.printStackTrace();
}
}
}

This json Result appears what you got from your api URL . Right ??
{
"person":[
{
"name":"John",
"city":"Mumbai"
},
{
"name":"Rahul",
"city":"Delhi"
},
{
"name":"Sanjana",
"city":"Amritsar"
},
{
"name":"Anjali",
"city":"Hyderabad"
},
{
"name":"Mukund",
"city":"Bangalore"
},
{
"name":"Raunak",
"city":"Patna"
}
],
"updated":{
"time":"14:17:48",
"date":"2016-04-10"
},
"error":"2353"
}
Now Here is a Code how to Iterate or parse your json Object. I Suppose that above Result json is stored in a String Variable String genreJson as per Your Code.
Here I wrote a method to solve your Problem. You may take a reference of it and may try your own code.
public void testYourJSON(String genreJson){
JSONParser parser=new JSONParser(); //parser used to parse String to Correct Json format.
JSONObject obj_ComplexData = (JSONObject) parser.parse(genreJson); // Now Your String Converted to a JSONObject Type.
//person tag Array Data is fetched and Stored into a JSONArray Object.
JSONArray obj_arrayPersonData = (JSONArray) parser.parse(obj_ComplexData.get("person").toString());
for (Object person : obj_arrayPersonData ) { //Iterate through all Person Array.
System.out.println(person.get("name"));
System.out.println(person.get("city"));
}
//Select "updated" Tag Json Data.
JSONObject obj_Updated = (JSONObject) parser.parse(obj_ComplexData.get("updated").toString());
System.out.println(obj_Updated.get("time")); //display time tag.
System.out.println(obj_Updated.get("date")); //display date tag.
System.out.println(obj_Updated.get("error")); //display Your Error.
}

Try this
public static String[] getInfo(String url)
{
String result=//I am assuming your json response is in result
String[] titles=null;
try {
JSONObject jsonObject=new JSONObject(result);
JSONObject temp=null;
JSONArray jsonArray=jsonObject.getJSONArray("person");
int length=jsonArray.length();
person=new String[length];
for (int i=0;i<length;i++){
temp= (JSONObject) jsonArray.get(i);
titles[i]=temp.getString("name")+temp.getString("city");
}
} catch (JSONException e) {
e.printStackTrace();
}
return titles;
}
This works fine, if you face any problem write in comments.
Happy coding!!

Getting string from Json

I am new in json.My question is very simple.I have some array in my json file and also a string type of data.
Now I want to get the single text, name: anounce in my java class from json file.
How can i get this string from json ?
or any other way to get this ?
Json file
[{
"title": "KalerKantha | OfftechIT",
"image": "",
"link": "http://www.kalerkantho.com/"
}, {
"title": "Prothom Alo | OfftechIT",
"image": "",
"link": "http://www.prothom-alo.com/"
},
...
{
"anounce": "I need this this text"
}
]
Java Code
JsonArrayRequest movieReq = new JsonArrayRequest(url, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
Movie movie = new Movie();
movie.setTitle(obj.getString("title"));
movie.setThumbnailUrl(obj.getString("image"));
movie.setLink(obj.getString("link").toString());
// adding movie to movies array
movieList.add(movie);
} catch (JSONException e) {
e.printStackTrace();
}
}
// notifying list adapter about data changes
// so that it renders the Grid view with updated data
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
if (error instanceof NoConnectionError){
hidePDialog();
Toast.makeText(getActivity(), " No Internet connection! \n Please check you connection", Toast.LENGTH_LONG).show();
}};
});

You simply make check the announce is present in the JSON or not
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
if(obj.has("anounce"))
{
String anounce= obj.getString("anounce");
}
else
{
Movie movie = new Movie();
movie.setTitle(obj.getString("title"));
movie.setThumbnailUrl(obj.getString("image"));
movie.setLink(obj.getString("link").toString());
// adding movie to movies array
movieList.add(movie);
}
} catch (JSONException e) {
e.printStackTrace();
}

Use optString method. It would return the value if node exists and String.empty is node is not found.
From Documentation
public String optString (String name)
Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
Do this
try {
JSONObject obj = response.getJSONObject(i);
String announce = obj.optString("anounce");
Movie movie = new Movie();
movie.setTitle(obj.optString("title"));
movie.setThumbnailUrl(obj.optString("image"));
movie.setLink(obj.optString("link"));
// adding movie to movies array
movieList.add(movie);
} catch (JSONException e) {
e.printStackTrace();
}
Update: Using optString is much better, but if you don't want to use it then do this
try {
JSONObject obj = response.getJSONObject(i);
if(i == response.length() -1)
{
String announce = obj.getString("anounce");
}
else
{
Movie movie = new Movie();
movie.setTitle(obj.getString("title"));
movie.setThumbnailUrl(obj.getString("image"));
movie.setLink(obj.getString("link").toString());
// adding movie to movies array
movieList.add(movie);
}
} catch (JSONException e) {
e.printStackTrace();
}

The Structure of your JSON is hard. But if you really want to get the string. Try this. Add this inside in for loop.
String data = (obj.getString("announce") != null) ? obj.getString("announce") : "";
// If you Movie has this annouce in your settler Getter if not try to add it.
Movie.setAnnounce(data);

Your code look like good but Are you add the request to queue
like:-
AppController.getInstance().addToRequestQueue(movieReq);
movieReq is JsonArrayRequest,
Please check it. and
String manounce=obj.getString("anounce");

Parse multiple items in JSON into an array

I have a client that retrieves some json from this page. The json content looks like this:
{
"0": {
"name": "McDonalds 2",
"address": "892 West 75th Street, Naperville, IL 60540"
},
"1": {
"name": "McDonalds 1",
"address": "1298 South Naper Boulevard, Naperville, IL 60540"
},
"2": {
"name": "Burger King 1",
"address": "2040 Aurora Avenue, Naperville, IL, 60540"
}
}
I'm having problems parsing it. I always get an exception when trying to parse anything. It's my first time doing json so I might be doing something really bad. This is my code:
public static void parse(String jsonData)
{
JSONObject jsonObject = new JSONObject();
try
{
jsonObject = new JSONObject(jsonData);
}
catch (JSONException e)
{
e.printStackTrace();
}
try
{
// exception happens here when trying to access data
JSONObject name = ((JSONArray)jsonObject.get("0")).getJSONObject(0)
.getJSONObject("name");
JSONObject address = ((JSONArray)jsonObject.get("0")).getJSONObject(0)
.getJSONObject("address");
} catch (JSONException e) {}
}
How an I retrieve the name and address of each json item to convert it into a restaurant object?

The format of the JSON is wrong. Please refer to this link and the right code is below. You will know what to do.
public static void parse(String jsonData) {
ArrayList<Restaurant> restaurantList= new ArrayList<Restaurant>();
JSONObject jsonObject;
JSONObject jsonRestaurant;
try {
jsonObject= new JSONObject(jsonData);
for(int i=0;i<3;i++) {
Restaurant restaurant= new Restaurant();
jsonRestaurant= jsonObject.getJSONObject(Integer.toString(i));
restaurant.name= jsonRestaurant.getString("name");
restaurant.address= jsonRestaurant.getString("address");
restaurantList.add(restaurant);
}
}
catch(JSONException e) {
e.printStackTrace();
}
}