Develop Reference

Having trouble parsing json using volley

I'm trying to get data from flickr API, using volley lib.
this is my json :
{
"photos": {
"page": 1,
"pages": 48,
"perpage": 100,
"total": "4793",
"photo": [
{
*"id": "48955365182",
"owner": "49191827#N00",
*"secret": "fd5e5fd91c",
*"server": "65535",
* "farm": 66,
"title": "permitted burn. thermal, ca. 2019.",
"ispublic": 1,
"isfriend": 0,
"isfamily": 0
}, ...
}
}
I'm trying to get the fields with " * ":
private void parseJson() {
String URL = "https://www.flickr.com/services/rest/?method=flickr.people.getPublicPhotos&api_key=x&user_id=49191827%40N00&extras=&format=json&nojsoncallback=1";
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, URL, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
JSONArray jsonArray ;
try {
jsonArray = response.getJSONArray("photo");
for(int i=0; i<jsonArray.length(); i++){
JSONObject jsonObject = (JSONObject) jsonArray.get(i);
Log.d("GGG",jsonObject.getString("secret"));
Log.d("GGG",jsonObject.getString("id"));
}
} catch (JSONException e) {
e.printStackTrace();
Log.d("VVV",e.getMessage());
}
}
}, new Response.ErrorListener() {
}
}
);
}

You need to parse from the very top object
jsonArray = response.getJSONObject("photos").getJSONArray("photo")

Unable to extract jsonarray from jsonobject

I have been battling with response from server using retrofit.
I have this json response from server
{
"success": true,
"message": "Your Requests",
"data": {
"requests": [
{
"_id": "5d163a5ed2399f8be6d8d867",
"created": "2019-06-28T16:03:42.463Z",
"pickupCoordinates": [
8.0099,
6.0909
],
"destinationCoordinates": [
9.088788,
3.099403
],
"customerName": "Seun Akinbode",
"pickupAddress": "Lekki",
"destinationAddress": "Ajah",
"accessCode": "3334",
"busPlate": "DD222RR",
"flaName": "Simi",
"flaEmail": "awele#kobo360.com",
"__v": 0
} ]
}
I use below class to parse the json but unfortunately, it couldn't extract the array requests into jsonArray
public ArrayList<RequestModel> getData(String response)
{
Log.d("responseData :", response);
ArrayList<RequestModel> dataList = new ArrayList<>();
try {
JSONObject mainObj = new JSONObject(response);
JSONArray array = mainObj.getJSONArray("data");
Log.d("The main Array :", array.toString());
RequestModel data;
for(int i = 0;i<array.length();i++)
{
data = new RequestModel();
JSONObject resObj = array.getJSONObject(i);
JSONArray reqArray = resObj.getJSONArray("requests");
for( int j =0;j<reqArray.length();j++) {
JSONObject reqObj = reqArray.getJSONObject(j);
data.setAccessCode(reqObj.getString("accessCode"));
Log.d("Accessecode :", reqObj.getString("accessCode"));
data.setCustomerName(reqObj.getString("customerName"));
Log.d("customerName :", reqObj.getString("customerName"));
}
dataList.add(data);
}
} catch (Exception e) {
e.printStackTrace();
}
return dataList;
}
Logcat is printing the JSONObject but it says at ... data of type org.json.JSONObject cannot be converted to JSONArray

You are trying to extract an array from the data field, while the response contains an object. Perhaps you meant to get the object data, then the array requests from within it.

This could be the problem:
JSONArray array = mainObj.getJSONArray("data");
data is an object as seen in the response, not an array.

JSON file processing with a different structure

I have an android app (Java) that processes an API from te web.
Currently the app is processing a JSON file that looks like this:
{
"contacts": [
{
"id": 1,
"name": "name1",
"email": "email1",
"phone": "1234567890"
},
{
"id": 2,
ETC...
I need to process another JSON file but it has a different structure:
{
"contacts": {
"1": {
"id": 1,
"name": "name1",
"email": "email1",
"phone": "1234567890",
"level1": {
"level2": {
"level3": 3,
}
},
"last_updated": 20180712
},
"2": {
ETC...
How do I process this second JSON file by adjusting the below code?
if (jsonSource != null) {
try {
JSONObject jsonObject = new JSONObject(jsonSource);
JSONArray jsonArrayData = jsonObject.getJSONArray("contacts");
for (int i = 0; i < jsonArrayData.length(); i++) {
JSONObject contacts = jsonArrayData.getJSONObject(i);
String id = contacts.getString("id");
String name = contacts.getString("name");
String email = contacts.getString("email");
String phone = contacts.getString("phone");
HashMap<String, String> values = new HashMap<>();
values.put("id", id);
values.put("name", name);
values.put("email, email);
values.put("phone, phone);
contactList.add(values);
}
} catch (final JSONException e) {
Log.e(TAG, "JSON parsing error: " + e.getMessage());
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getContext(), "ERROR", Toast.LENGTH_LONG).show();
}
});
}
} else {
Log.e(TAG, "Unable to retrieve JSON file from URL");
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getContext(), "ERROR", Toast.LENGTH_LONG).show();
}
});
}
return null;
Any help is much appreciated!

It looks, that inside first json you have "contacts" as array of objects, and inside second one you have "contacts" as object. Inside it you have other objects, simplified version looks like this:
"contacts": [
{...},
{...},
{...}
]
"contacts": {
"1": {...},
"2": {...},
"3": {...}
}
So, the only option you have is to check manually is "contacts" array or object, and based on it change your code.
It would look like this:
JSONObject jsonObject = new JSONObject(jsonSource);
if (jsonObject.get("contacts") instanceof JSONObject) {
JSONObject contactsJson = jsonObject.getJSONObject("contacts");
for (Iterator<String> it = contactsJson.keys(); it.hasNext(); ) {
String key = it.next();
JSONObject contactJson = contactsJson.getJSONObject(key);
// your code to process contact item
}
} else {
// Your code to process every contact item
}

Parse nested Json object and store in database in Android

I just tried to get values that are stored in my JSON file and save it into sqlite database:
This is my JSON file:
{
"list": {
"meta": {
"count": 132,
"start": 0,
"type": "resource-list"
},
"resources": [
{
"resource": {
"classname": "Quote",
"fields": {
"date": "2017-03-16",
"price": 3.6720000000000002,
"type": "currency",
"symbol": "AED=X"
}
}
},
{
"resource": {
"classname": "Quote",
"fields": {
"date": "2017-03-16",
"price": 65.075000000000003,
"type": "currency",
"symbol": "AFN=X"
}
}
},
{
.............
}
............
I have tried like this but getting exception :
JSONObject mainObj = null;
try {
mainObj = new JSONObject(JSON);
JSONObject getSth = mainObj.getJSONObject("list");
if(mainObj != null){
JSONArray list = getSth.getJSONArray("resources");
if(list != null){
for(int i = 0; i < list.length();i++){
JSONObject elem = list.getJSONObject(i);
if(elem != null){
JSONObject prods = elem.getJSONObject("fields");
Object level = prods.get("type");
Toast.makeText(getApplicationContext(),""+level.toString(),Toast.LENGTH_LONG).show();
}
}
}
}
}catch (Exception e){
Toast.makeText(getApplicationContext(),""+e.toString(),Toast.LENGTH_LONG).show();
}
I was getting exception : no values in fields...
And pls give some suggestions that storing these values in Database table(matrotable) of(row fields) name, prize, symbol and type, I may try by making String Array and retrieving and storing the values for sqlite, is there any other easy options...
thanks

your fields objects are inside resource object so do
for(int i = 0; i < list.length();i++){
JSONObject elem = list.getJSONObject(i);
if(elem != null){
JSONObject prods = elem.getJSONObject("resource")
.getJSONObject("fields");
Object level = prods.get("type");
Toast.makeText(getApplicationContext(),""+level.toString(),Toast.LENGTH_LONG).show();
}
}
"resources": [ // resources list
{ // object i
"resource": { // fields are inside "resource" object
"classname": "Quote",
"fields": {
"date": "2017-03-16",
"price": 3.6720000000000002,
"type": "currency",
"symbol": "AED=X"
}
}
}

You are missing the resource JOSNObject parsing...
for(int i = 0; i < list.length();i++){
JSONObject elem = list.getJSONObject(i);
JSONObject resource = elem.getJSONObject("resource");
if(resource != null){
JSONObject prods = resource.getJSONObject("fields");
Object level = prods.get("type");
Toast.makeText(getApplicationContext(),""+level.toString(),Toast.LENGTH_LONG).show();
}
}

I recommend to you to use the simplest and easiest way to parse a json response to avoid this kind of issues:
1- generate your model classes by using this tool: http://www.jsonschema2pojo.org/ download and add the generated classes to your model package.
2- add this dependency to your gradle file:
compile 'com.google.code.gson:gson:2.4'
3- Call this method to parse your response:
Gson gson = new Gson();
ResponseModel responseModel = gson.fromJson(json, ResponseModel.class);

Trouble with Parsing JSONObject in java

I am having trouble parsing this particular JSONObject,
Here is the object:
{"status":1,"dds":{"id":1,"name":"DDS1","description":"This is DDS 1","children":[{"id":2,"order":1,"type":1,"children":[{"id":3,"order":1,"type":3,"children":[]},{"id":4,"order":2,"type":2,"children":[]}]}]}}
That object is stored in my variable called result, here is my code to parse it:
JSONObject jsonObj = null;
JSONArray jsonArr = null;
try {
jsonObj = new JSONObject(result);
jsonArr = jsonObj.getJSONArray("dds");
} catch (JSONException e) {
e.printStackTrace();
}
And it is giving me this error:
org.json.JSONException: Value {"id":1,"children":[{"type":1,"order":1,"id":2,"children":[{"type":3,"order":1,"id":3,"children":[]},{"type":2,"order":2,"id":4,"children":[]}]}],"description":"This is DDS 1","name":"DDS1"} at dds of type org.json.JSONObject cannot be converted to JSONArray
I am trying to break it up into sub arrays of children. Where am I going wrong?
#Mr Love
here is my output to your code

You are calling jsonArr = jsonObj.getJSONArray("dds");, however dds is not an array, it's a JSON object, if you format the JSON you can see it clearly:
{
"status":1,
"dds":{
"id":1,
"name":"DDS1",
"description":"This is DDS 1",
"children":[
{
"id":2,
"order":1,
"type":1,
"children":[
{
"id":3,
"order":1,
"type":3,
"children":[
]
},
{
"id":4,
"order":2,
"type":2,
"children":[
]
}
]
}
]
}
}
So you will just need to call JSONObject dds = jsonObj.getJSONObject("dds"), and if you want the children you would call JSONArray children = jsonObj.getJSONObject("dds").getJSONArray("children");.
private static final String json = "{\"status\":1,\"dds\":{\"id\":1,\"name\":\"DDS1\",\"description\":\"This is DDS 1\",\"children\":[{\"id\":2,\"order\":1,\"type\":1,\"children\":[{\"id\":3,\"order\":1,\"type\":3,\"children\":[]},{\"id\":4,\"order\":2,\"type\":2,\"children\":[]}]}]}}";
public static void main(String[] args) throws JSONException
{
JSONObject jsonObj = new JSONObject(json);
JSONObject dds = jsonObj.getJSONObject("dds");
JSONArray children = dds.getJSONArray("children");
System.out.println("Children:");
System.out.println(children.toString(4));
JSONArray grandChildren = children.getJSONObject(0).getJSONArray("children");
System.out.println("Grandchildren:");
System.out.println(grandChildren.toString(4));
}
Produces:
Children:
[{
"children": [
{
"children": [],
"id": 3,
"order": 1,
"type": 3
},
{
"children": [],
"id": 4,
"order": 2,
"type": 2
}
],
"id": 2,
"order": 1,
"type": 1
}]
Grandchildren:
[
{
"children": [],
"id": 3,
"order": 1,
"type": 3
},
{
"children": [],
"id": 4,
"order": 2,
"type": 2
}
]

You can do it like this, where the JsonElement could be a JSONobject or JsonArray or any primitive type:
private JsonElement findElementsChildren(JsonElement element, String id) {
if(element.isJsonObject()) {
JsonObject jsonObject = element.getAsJsonObject();
if(id.equals(jsonObject.get("id").getAsString())) {
return jsonObject.get("children");
} else {
return findElementsChildren(element.get("children").getAsJsonArray(), id);
}
} else if(element.isJsonArray()) {
JsonArray jsonArray = element.getAsJsonArray();
for (JsonElement childElement : jsonArray) {
JsonElement result = findElementsChildren(childElement, id);
if(result != null) {
return result;
}
}
}
return null;
}