Develop Reference

De-serializing nested JSON to Java in Android Studio

I'm trying to deserialize this JSON to an array of Java objects of class Mural and show them in a list (Recycler View) in my app. Here's formatted example of the JSON with only the data that I need.
{
"records": [{
"recordid": "e6b10b2f7cadbe7caec9a0b36e9e7b570c3add50",
"fields": {
"auteur_s": "Dupa",
"photo": {
"id": "7cd8a2bc799826835057eaec21a28730",
},
"annee": "1994",
"coordonnees_geographiques": [50.8527886675,
4.34530735016],
"personnage_s": "Cubitus - Dommel"
},
},
...
]
}
I use Okhttp to make the request and the response is successful, so I use it to construct a JSONObject.
I traverse the "records" array in that object, because that's where I find all the data I need. Keys that have a string or an array as value work fine and I can load them into my app's Recycler View, but when I want to access "photo", i.e. a key:value pair nested within another object, I get a JSONException org.json.JSONException: No value for photo and my Recycler View returns empty.
Here's what the code looks like:
private void fetchMurals(){
threadExecutor.execute(new Runnable() {
#Override
public void run() {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://bruxellesdata.opendatasoft.com/api/records/1.0/search/?dataset=comic-book-route&rows=58")
.get()
.build();
try{
Response response = client.newCall(request).execute();
String json = response.body().string();
JSONObject jsonObject = new JSONObject(json);
JSONArray jsonRecordsArray = jsonObject.getJSONArray("records");
int arraySize = jsonRecordsArray.length();
muralArrayList = new ArrayList<>();
for (int i = 0; i < arraySize; i++){
String jsonID = jsonRecordsArray.getJSONObject(i).getString("recordid");
JSONObject jsonMural = jsonRecordsArray.getJSONObject(i).getJSONObject("fields");
JSONObject jsonMuralPhoto = jsonMural.getJSONObject("photo");
final Mural currentMural = new Mural(
jsonID,
(jsonMural.has("auteur_s")) ? jsonMural.getString("auteur_s") : "Unknown Author",
(jsonMuralPhoto.has("id")) ? jsonMuralPhoto.getString("id") : "No picture available!",
(jsonMural.has("personnage_s")) ? jsonMural.getString("personnage_s") : "Unknown character",
(jsonMural.has("annee")) ? jsonMural.getString("annee") : "Unknown year of creation",
new LatLng(jsonMural.getJSONArray("coordonnees_geographiques").getDouble(0),
jsonMural.getJSONArray("coordonnees_geographiques").getDouble(1))
);
muralArrayList.add(currentMural);
} catch (IOException e){
e.printStackTrace();
}
});
}
I've tried many variations of this but none have worked so far. Could it be a problem with my loop? Or with the jsonMural.getJSONObject("photo") that I am calling?

I see now that I was checking if my record had the field "id" whereas I should have been checking if it had "photo". I changed the line in my constructor to
(jsonArtwork.has("photo")) ? jsonArtwork.getJSONObject("photo").getString("id") : "No picture available!"
Works now.

Parse Json array without keys

I want to parse an array from Server but I can't obtain the array
Here is the jsonString Successfully got :
{
"status":"OK",
"message":"this is your start and end coordinates",
"data":"{\"start\":[\"35.778763\",\"51.427360\"],\"end\":[\"35.768779, 51.415002\"]}"
}
I want the Double Values from data arraylist:
//try/catch
Log.d(TAG, "Passes here");
JSONObject jObject = new JSONObject(jsonString);
JSONArray jData = jObject.getJSONArray("data");
Log.d(TAG, "Not PAASING HERE !!! ");
JSONArray jArrayStart = (JSONArray) jData.get(0);
JSONArray jArrayEnd = (JSONArray) jData.get(1);
latitudeStart = (Double) jArrayStart.get(0);
longtitudeStart = (Double) jArrayEnd.get(1);
latitudeEnd = (Double) jArrayEnd.get(0);
longtitudeEnd = (Double) jArrayEnd.get(1);

What you're trying to parse, is a string.
{
"status": "OK",
"message": "this is your start and end coordinates",
"data": "{\"start\":[\"35.778763\",\"51.427360\"],\"end\":[\"35.768779, 51.415002\"]}"
}
So it works like this:
//first, retrieve the data from the response JSON Object from the server
JSONObject response = new JSONObject(jsonString);
String status = response.getString("status");
String message = response.getString("message");
//Note this: "data" is a string as well, but we'll have to parse that later.
String data = response.getString("data");
//get the doubles from the arrays from the "data" component.
JSONObject dataObject = new JSONObject(data);
JSONArray start = dataObject.getJSONArray("start");
JSONArray end = dataObject.getJSONArray("end");
for (int i = 0; i < start.length(); i++) {
String value = start.getString(i);
//do something with the start String (parse to double first)
}
for (int i = 0; i < end.length(); i++) {
String value = end.getString(i);
//do something with end String (parse to double first)
}
So data is actually a String, but represents a JSONObject (which you'll have to parse), which, in its turn, contains two JSONArrays.
If data was a JSONObject instead of a String, the JSON would have looked like this:
{
"status": "OK",
"message": "this is your start and end coordinates",
"data": {
"start": [
"35.778763",
"51.427360"
],
"end": [
"35.768779", //note that in your example, this quote is missing (first quote on next line too)
"51.415002"
]
}
}

The value of data is not a JSONArray its JSONObject
Explanation
JSONObject will be surrounded by {}
JSONArray will be surrounded by []

data is not an array, it is a json object and therefore you can not access it the way you are doing.
If you want to fetch start array from json object "data" then use below
jObject.optJSONObject("data").optJSONArray("start");
same thing can be used to retrieve "end" json array.
then use optJSONObject() and/or optString() API to retrieve required value from json array.

parse json array in android

I need a help... I have a php file which returns me two json Arrays which are as follows:
[{ "id":"1",
"item":"hammers",
"aisle":"20"
}
{ "id":"1",
"item":"hammers",
"aisle":"20"
}]
[{ "id":"1",
"itemFound":"Your item #item",
"ThankYou":"and Thank You for using Txtcore!"
}]
Now, I want to get the second array items in Android. I have the following code now which is like :
JSONArray jsonArray = new JSONArray(result);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
items.add(jsonObject.getString("item"));
aisles.add(""+jsonObject.getString("item");
}
But obviously, that returns me the objects from the first array. I want to get the Objects from the second array. Any suggestions.

Your JSON is not valid but u can get your element as follows. It is a solution from many(just a worlaround).
String str = "YOUR_JSON_RESPONSE";
String array[] = str.split("\\[\\{");//
try {
JSONArray jsonArray=new JSONArray("[{" + array[2]));
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

I guess you'll have to do some dirty coding because the data return by the PHP page is not well formed JSON.
You could try to transform the JSON data to:
{ "data" : [ <array_1>, <array_2> ]} And then use the JSON parser. A simple replacement with a regexp could be fine.
result.replaceAll("\\]\\s*\\[", "], [");
StringBuffer buffer=new StringBuffer(result);
buffer.insert(0,"{ \"data\": ");
buffer.append(" }");
JSONObject jsonObject = new JSONObject(buffer.toString());
JSONArray secondArray= jsonObject.getJSONArray("data").getJSONArray(1);
The creation of a valid JSON string can be done in one step with the appropriate regexp. Hope some one with more time can post it here.

How to convert int Array to JSON String in Android?

I expected to find this question around, but I couldn't. Maybe I'm Googling the wrong thing.
I have a primitive integer array (int[]), and I want to convert this into a String, that is "JSON-Parseable", to be converted back to the same int[].
What have I tried :
I tried this code :
// int[] image_ids_primitive = ...
JSONArray mJSONArray = new JSONArray(Arrays.asList(image_ids_primitive));
String jSONString = mJSONArray.toString();
Prefs.init(getApplicationContext());
Prefs.addStringProperty("active_project_image_ids", jSONString);
// Note: Prefs is a nice Class found in StackOverflow, that works properly.
When I printed the jSONString variable, it has the value : ["[I#40558d08"]
whereas, I expected a proper JSON String like this : {"1" : "424242" , "2":"434343"} not sure about the quotation marks, but you get the idea.
The reason I want to do this :
I want to keep track of local images (in drawable folder), so I store their id's in the int array, then I want to store this array, in the form of a JSON String, which will be later parsed by another activity. And I know I can achieve this with Intent extras. But I have to do it with SharedPreferences.
Thanks for any help!

You don't have to instantiate the JSONArray with Arrays.asList. It can take a normal primitive array.
Try JSONArray mJSONArray = new JSONArray(image_ids_primitive);
If you are using an API level below 19, one easy method would just be to loop over the int array and put them.
JSONArray mJSONArray = new JSONArray();
for(int value : image_ids_primitive)
{
mJSONArray.put(value);
}
Source: Android Developers doc

If you want a JSON array and not necessarily an object, you can use JSONArray.
Alternatively, for a quick hack:
System.out.println(java.util.Arrays.toString(new int[]{1,2,3,4,5,6,7}));
prints out
[1, 2, 3, 4, 5, 6, 7]
which is valid JSON. If you want anything more complicated than that, obviously JSONObject is your friend.

Try this way
int [] arr = {12131,234234,234234,234234,2342432};
JSONObject jsonObj = new JSONObject();
for (int i = 0; i < arr.length; i++) {
try {
jsonObj.put(""+(i+1), ""+arr[1]);
} catch (Exception e) {
}
}
System.out.println("JsonString : " + jsonObj.toString());

// If you wants the data in the format of array use JSONArray.
JSONArray jsonarray = new JSONArray();
//[1,2,1,] etc..
for (int i = 0; i < data.length; i++) {
jsonarray.put(data[i]);
}
System.out.println("Prints the Json Object data :"+jsonarray.toString());
JSONObject jsonObject=new JSONObject();
// If you want the data in key value pairs use json object.
// i.e {"1":"254"} etc..
for(int i=0;i<data.length;i++){
try {
jsonObject.put(""+i, data[i]);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("Prints the Json Object data :"+jsonObject.toString());

itertate this through the int array and you will get the json string
JSONStringer img = null ;
img = new JSONStringer() .object() .key("ObjectNAme")
.object() .key("something").value(yourIntarrayAtIndex0)
.key("something").value(yourIntarrayAtIndex1) .key("something").value(yourIntarrayAtIndex2)
.key("something").value(yourIntarrayAtIndex3)
.endObject() .endObject();
String se = img.toString();
Here se is your json string in string format

This code will achieve what you are after...
int index = 0;
final int[] array = { 100, 200, 203, 4578 };
final JSONObject jsonObject = new JSONObject();
try {
for (int i : array) {
jsonObject.put(String.valueOf(index), String.valueOf(i));
index++;
}
} catch (JSONException e) {
e.printStackTrace();
}
Log.d("YOUR_TAG", jsonObject.toString());
This will give you {"3" : "203", "2" : "200", "1": "100", "4": "4578"} as a string.
Not exactly sure why its not in the exact order, but sorting by a key is quite easy.

Extracting an array from a JSON object

I have a JSON Object of the following and I need to parse the path strings inside the web array into an new JSON array.
"taxonomy": {
"source": {
"master": {
"_id": "5000",
"path": "/Appliances/Refrigerators/French Door Bottom Freezers"
},
"web": [
{
"_id": "6686",
"path": "/Appliances/Refrigerators/French Door Bottom Freezers"
},
{
"_id": "7686",
"path": "/Appliances/Refrigerators/Bottom Freezers"
}
],
},
},
I have written till this but I'm not sure how to get all the path inside the web array.
JSONObject jsonTaxonomy= _blob.optJSONObject("taxonomy");
if(jsonTaxonomy!=null)
{
if(!jsonTaxonomy.isNull("source"))
{
JSONObject jsonTaxonomySource= jsonTaxonomy.optJSONObject("source");
if(!jsonTaxonomySource.isNull("web"))
{
JSONArray jsonTaxonomySourceWeb= jsonTaxonomySource.optJSONArray("web");
if(jsonTaxonomySourceWeb!=null && jsonTaxonomySourceWeb.length()>0)
{
//Got inside the array
}
}
}
}

Without providing you with a full answer, I'm convinced you'll be able to find your answer by debugging this method and stopping it at the most inner if(). You'll be able to of what jsonTaxonomySearsWeb consists and thus how to get its values.

Modify your code to something like this:-
JSONObject jsonTaxonomy= _blob.optJSONObject("taxonomy");
if(jsonTaxonomy!=null)
{
JSONObject jsonTaxonomySource = jsonTaxonomy.optJSONObject("source");
if(jsonTaxonomySource!=null)
{
JSONArray jsonTaxonomySearsWeb= jsonTaxonomySource.optJSONArray("web");
if(jsonTaxonomySearsWeb!=null)
{
// Traverse through your JSONArray and get each Object & extract path from it.
}
}
}

I am bit unclear about the question. But As per my understanding you want to parse the JSON if you want to do that in java then you can use GSON jar from google...you can also check simple example here Gson handle object or array

Try like this...
groups = json.getJSONArray(TAG_GROUP);
System.out.println("Result Success+++"+groups);
for (int i = 0; i < groups.length(); i++) {
JSONObject c = groups.getJSONObject(i);
String source = c.getString(TAG_SOURCE);
System.out.println("Checking ::"+source);
String lname = c.getString(TAG_PATH);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_SOURCE, source);
map.put(TAG_PATH,path);
weblist.add(map); //weblist is your arraylist for both values
webpathlist.add(path); //webpathlist is your arraylist for path
}
List<String> newList = new ArrayList<String>();
newList.addAll(weblist);