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Java jsonObject.get() returns null or an empty object for specific key [duplicate]

This question already has answers here:
Json object returning null against given key
(3 answers)
Closed 5 years ago.
Here's the JSON response.
The following works:
jsonObject.get("title").getAsString();
jsonObject.get("author").getAsJsonObject().get("profile_photo").getAsString();
but jsonObject.get("primary_photo").getAsString() (from line 60) returns an Unsupported Exception: null error. I've tried replacing getAsString() with toString() but the latter returns an empty string.

Try this
Use optJSONObject and optString in your code . And the root is [],so you should use JSONArray
try {
JSONArray jsonArray = new JSONArray(response);
for (int i = 0; i < jsonArray.length(); i++) {
// use optJSONObject
JSONObject author = jsonArray.optJSONObject(i).optJSONObject("author");
// use optString , it did not return null
String profile_photo = author.optString("profile_photo");
String primary_photo = jsonArray.optJSONObject(i).optString("primary_photo");
}
} catch (JSONException e) {
e.printStackTrace();
}
Gson
JsonArray jsonElements = new JsonParser().parse(response).getAsJsonArray();
for (int i = 0; i < jsonElements.size(); i++) {
JsonObject jObject = jsonElements.get(i).getAsJsonObject();
// edited here
String primary_photo = jObject.get("primary_photo").getAsString();
JsonObject author = jObject.getAsJsonObject("author");
String profile_photo = author.get("profile_photo").getAsString();
}

I think the Problem is, that your JSON response contains an Array. You have to create an JSONArray from the response-string and than iterate about it to get your values. Or if this array always contains one object:
JSONArray jsonArray = new JSONArray(response);
JSONObject jsonObject = jsonArray.getJSONObject(0);

Try this,
try {
JSONArray jsonArray = new JSONArray(response);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject author = jsonArray.get(i).getJSONObject"author");
String profile_photo = author.getString("author");
}
} catch (JSONException e) {
e.printStackTrace();
}

Try this:
try {
JSONArray jarr=new JSONArray(response); // response is whole json response
for (int i=0;i<jarr.length();i++){
JSONObject jobj=jarr.getJSONObject(i);
String primary_photo=jobj.getString("primary_photo");
}
} catch (JSONException e) {
e.printStackTrace();
}

Having trouble finding the right JSON path for android project

JSONObject baseJsonResponse = new JSONObject(newsJSON);
JSONObject responseObj = baseJsonResponse.getJSONObject("response");
JSONArray resultArray = responseObj.getJSONArray("results");
for (int i =0;i<resultArray.length();i++){
String sectionName = resultArray.getString("sectionName");}
I want to get the section name for this url:
https://content.guardianapis.com/search?api-key=e11b8d10-d6ef-4fb7-9c12-094c58d37687

You can get Json Value Like this.
JSONObject baseJsonResponse = new JSONObject(newsJSON);
JSONObject responseObj = null;
try {
responseObj = baseJsonResponse.getJSONObject("response");
JSONArray resultArray = responseObj.getJSONArray("results");
int size = resultArray.length();
for (int i =0;i<size;i++){
JSONObject myJson = resultArray.getJSONObject(i);
String sectionName = myJson.getString("sectionName");
}
} catch (JSONException e) {
e.printStackTrace();
}

How to convert jsonstring to jsonobject in android?

i tried to convert jsonstring to json object. but its convert only first element.
here is my code
String d = [{"name":"kd","isMe":"yes","time":"10:12 AM"},{"name":"you","isMe":"no","time":"10:12 AM"}]
JSONObject j = new JSONObject(d);
its give following output
{"name":"kd","isMe":"yes","time":"10:12 AM"}
how can i convert this string into JSNOObject?

You can try like this, and your root is Json array not jsonobject
try {
JSONArray jsonArray = new JSONArray(d);
if(jsonArray != null) {
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.optJSONObject(i);
if(jsonObject == null) {
continue;
}
String name = jsonObject.optString("name");
String isMe = jsonObject.optString("isMe");
String time = jsonObject.optString("time");
}
}
} catch (JSONException e) {
e.printStackTrace();
}

Use this
JSONObject jsonObject = new JSONObject(my_json_string);
JSONArray jresult = jsonObject.getJSONArray("array_in_the_json_string");

Trying to parse JSON in Android

How would you suggest me to parse this JSON:
{"17": {"user_name": "test1"}, "18": {"user_name": "test5"}, "19": {"user_name": "test9"}}
I need to get "username",but i cant find the way to do it. Maybe i should change JSON to something like that:
[{"user_name": "test1"},{"user_name": "test5"},{"user_name": "test9"}]
This way i tried to get "user_name"s:
try {
List<String> allNames = new ArrayList<String>();
String str = "[{"user_name": "test1"},{"user_name": "test5"},{"user_name": "test9"}]";
JSONObject json = new JSONObject(str);
for ( int i = 0; i < json.length() ; i++)
{
JSONObject actor = json.getJSONObject(i);
String user_name = actor.getString("user_name");
allNames.add(user_name);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
But then i get Problem with that line:
JSONObject actor = json.getJSONObject(i);
Android studio tells me that JSONObject cannot be applied to int(i). I have no idea why it doesn't work.
Can somebody please give me some hint, tutorial or an example?
Much appreciated !

The method JSONObject.getJSONObject requires a String argument (the name or key of the object), not an int. In your case, the keys are "17", "18" and "19". To get all keys, use the JSONObject.keys() method:
JSONObject json = new JSONObject(str);
Iterator<String> keyIterator = json.keys();
while (keyIterator.hasNext()) {
JSONObject actor = json.getJSONObject(keyIterator.next());
String user_name = actor.getString("user_name");
allNames.add(user_name);
}

Android studio tells me that JSONObject cannot be applied to int(i)
Because JSONObject.getJSONObject method takes key name as String instead of int. and keys in posted json is 17,18,... to access inner JSONObject.
To get all user_name from JSONObject,need to get all keys:
Iterator<String> iter = json.keys();
while (iter.hasNext()) {
String key = iter.next();
JSONObject actor = json.getJSONObject(key);
String user_name = actor.getString("user_name");
allNames.add(user_name);
}

Change your code like this
try {
List<String> allNames = new ArrayList<String>();
String str = "[{"user_name": "test1"},{"user_name": "test5"},{"user_name": "test9"}]";
JSONOArray jsonArray = new JSONOArray(str);
for ( int i = 0; i < jsonArray .length() ; i++)
{
JSONObject actor = jsonArray.getJSONObject(i);
String user_name = actor.getString("user_name");
allNames.add(user_name);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

if you use the Gson library it's very easy.
String json = "{\"17\": {\"user_name\": \"test1\"}, \"18\": {\"user_name\": \"test5\"}, \"19\": {\"user_name\": \"test9\"}}";
Gson gson = new GsonBuilder().create();
Map<String,User> users = gson.fromJson(json, new TypeToken<Map<String,User> >(){}.getType());
for(String key : users.keySet()) {
Log.d("DEBUG",key+" -> "+users.get(key).getUser_name());
}
The User class is a simple POJO like:
public class User {
private String user_name;
public String getUser_name() {
return user_name;
}
public void setUser_name(String user_name) {
this.user_name = user_name;
}
}

str = {"17": {"user_name": "test1"}, "18": {"user_name": "test5"}, "19": {"user_name": "test9"}}
JSONObject ob1 = new JSONObject(str)
JSONObject ob2 = ob1.getJSONObject("17");
String userName = ob2.getString("user_name");
str = [{"user_name": "test1"},{"user_name": "test5"},{"user_name": "test9"}]
List<String> allNames = new ArrayList<String>();
JSONArray jsonArray = new JSONArray("str");
for(i=0; i < jsonArray.length(); i++){
JSONObject ob = jsonArray.getJSONObject(i);
allNames.add(ob.getString("user_name")
}

you are trying to parse JSONArray into JSONObject at
JSONObject json = new JSONObject(str);
use the below code.....
try {
List<String> allNames = new ArrayList<String>();
String str = "[{"user_name": "test1"},{"user_name": "test5"},{"user_name": "test9"}]";
JSONArray json = new JSONArray(str);
for ( int i = 0; i < json.length() ; i++)
{
JSONObject actor = json.getJSONObject(i);
String user_name = actor.getString("user_name");
allNames.add(user_name);
}
} catch (JSONException e) {
// TODO Auto-generated catch block`enter code here`
e.printStackTrace();
}

Get JSON Array into strings.

I have a webservice which returns a JSON array in this format:
[{"imageid":"3","userid":"1","imagepath":"SLDFJNDSKJFN","filterid":"1","dateadded":"2014-05-06 21:20:18.920257","public":"t"},
{"imageid":"4","userid":"1","imagepath":"dsfkjsdkfjnkjdfsn","filterid":"1","dateadded":"2014-05-06 21:43:37.642748","public":"t"}]
I need to get all the attributes seperately? How would I do this?
I know how to do it with JSONObject if there is just 1 thing being returned, but how does it work when multiple items are returned?
Thanks

try {
JSONArray jArray = new JSONArray(jsonString);
String s = new String();
for (int i = 0; i < jArray.length(); i++) {
s = jArray.getJSONObject(i).getString("imageid").toString();
s = jArray.getJSONObject(i).getString("userid").toString();
}
} catch (JSONException je) {
}

Create an Object class with all variables, create a List for this Object, add all objects in your JSONArray to the list, use the one you need.
List<YourObject> objList = new ArrayList<YourObject>();
JSONArray a = new JSONArray(response);
int size = a.length();
for (int i=0 ; i<size ; i++){
JSONObject aa = a.getJSONObject(i);
String id = aa.getString("imageid");
String userid = aa.getString("userid");
String imagepath = aa.getString("imagepath");
String filterid = aa.getString("filterid");
String dateadded = aa.getString("dateadded");
String publicText = aa.getString("public");
YourObject obj = new YourObject(id,userid,imagepath,filterid,dateadded,publicText);
objList.add(obj);
}

So what you are having here is some JSON objects inside a JSON array.
What you want to do is this:
JSONArray array = ...;
for (int i = 0; i < array.length(); i++) {
JSONObject o = array.getJSONObject(i);
// Extract whatever you want from the JSON object.
}
I hope it helped.

You can use JSONArray to parse array of JSON response.
private void parseJsonArray(String response) {
try {
JSONArray array = new JSONArray(response);
for(int i=0;i<array.length();i++){
JSONObject jsonObject = array.getJSONObject(i);
String ImageId = jsonObject.getString("imageid");
Log.v("JSON Parser", "ImageId: "+ImageId);
}
} catch (Exception e) {
e.printStackTrace();
}
}