Develop Reference

How should I parse JSON?

I am trying to parse this json.
However, it is not working ...
I want to parse expected_departure_time of all the buses such as 4 , 15, C1, 4A in departure
this is my code which is not working.
try{
String str = response.getString("departures");
JSONArray jsonArray = response.getJSONArray(str);
JSONObject bus = jsonArray.getJSONObject(0);
String four = bus.getString("expected_departure_time");
textView.append(four);
}catch (JSONException e){
e.printStackTrace();
}
JSON
https://transportapi.com/v3/uk/bus/stop/6090282/live.json?app_id=d7180b02&app_key=47b460aac35e55efa666a99f713cff28&group=route&nextbuses=yes

The error you're making is that you're considering "departures" as a JsonArray, which is not the case in your JSON example, it is a JsonObject (Which in my opinion is a poor way of constructing this Json).
Anyway, you will have to get all the JsonObjects inside the "departure" JsonObject by doing this:
try
{
String jsonString=response.toString();
JSONObject jObject= new JSONObject(jsonString).getJSONObject("departures");
Iterator<String> keys = jObject.keys();
while( keys.hasNext() )
{
String key = keys.next();
JSONArray innerJArray = jObject.getJSONArray(key);
//This is your example, you can add a loop here
innerJArray(0).getString("expected_departure_time");
}
}
catch (JSONException e)
{ e.printStackTrace(); }

If you need to use the transport API for other features, to convert JSON strings to Java objects, you can map automatically by using GSON.
Follow the instructions from Leveraging the gson library and map any response you want from this API.

Getting JSON Object without Key

It is possible to retrieve a JSON object without a key name?
One more problem is that it is deep in the hierarchy. Please see this: http://jsonviewer.stack.hu/#http://gateway.marvel.com/v1/public/characters?apikey=2d0af97a020cd072d49059aa0bf13207&hash=ef7184ddbb03ed2f71da0efec112cf41&ts=1495035369
That is an intensively long JSON and has multiple objects.
I am trying to access this part of the JSON: {
"id": 1010699,
"name": "Aaron Stack", ..
I am using the following code:
private void parseResult(String result) {
try {
JSONObject response = new JSONObject(result);
JSONArray posts = response.optJSONArray("data");
for (int i = 0; i < posts.length(); i++) {
JSONObject post = posts.optJSONObject(i);
String title = post.optString("results");
}
} catch (JSONException e) {
e.printStackTrace();
}
}
But I can't access it.

You can use GSON for this
compile 'com.google.code.gson:gson:2.7'
and create POJO class for the corroesponding json result using this link, Just paste your json data and create classes.
For eg your main pojo class name be JsonResponseHolder
And in your java code
try {
JsonResponseHolder jrh = new Gson().fromJson(responseString,
JsonResponseHolder.class);
List<Results> results = jrh.getData().getResults();
/// this will give the result objects
/// and be sure to convert [] arrays to list for better data handling
} catch (JSONException e) {
e.printStackTrace();
}
Hope this will help

Parsing JsonArray With JsonObject

I have some JSON with the following structure:
{
"items":[
{
"product":{
"product_id":"some",
"price_id":"some",
"price":"some",
"title_fa":"some",
"title_en":"Huawei Ascend Y300",
"img":"some",
"has_discount_from_price":"0",
"discount_from_price":null,
"type_discount_from_price":null,
"has_discount_from_product":"0",
"discount_from_product":null,
"type_discount_from_product":null,
"has_discount_from_category":"0",
"discount_from_category":null,
"type_discount_from_category":null,
"has_discount_from_brand":"0",
"discount_from_brand":null,
"type_discount_from_brand":null,
"weight":null,
"features":[
{
"feature_value":"#000000",
"feature_id":"some",
"feature_title":"some"
},
{
"feature_value":"some",
"feature_id":"1652",
"feature_title":"some"
}
]
},
"number":1,
"feature_id":"56491,56493",
"price_inf":{
"has_discount":0,
"discount_type":0,
"final_price":"400000",
"value_discount":0
},
"cart_id":13
}
]
}
I'm trying to access the elements "product_id" and "price_id" with the following Java code:
try{
JSONArray feedArray=response.getJSONArray("items");
for (int i=0;i<feedArray.length();i++){
JSONObject feedObj=feedArray.getJSONObject(i);
JSONObject pro=feedObj.getJSONObject("product");
Product product = new Product();
product.setPrice(pro.getDouble("price_id"));
product.setTitle_fa(pro.getString("price_id"));}}
but i see product not found error.what is wrong in my parser?

First of all your JSON is valid. So no worries there.
Now regarding your problem, because you haven't posted the logs so I can't tell what the exact problem is. But using this code snippet you can get the desired values.
try {
JSONArray itemsJsonArray = jsonObject.getJSONArray("items");
for (int i = 0; i < itemsJsonArray.length(); i++){
JSONObject itemJsonObject = itemsJsonArray.getJSONObject(i);
JSONObject productObject = itemJsonObject.getJSONObject("product");
String productId = productObject.getString("product_id");
String priceId = productObject.getString("price_id");
}
} catch (JSONException e) {
e.printStackTrace();
}

Validate and create Pojo for your json here
use
Data data = gson.fromJson(this.json, Data.class);
follow https://stackoverflow.com/a/5314988/5202007
By the way your JSON is invalid .

you are getting a json object from your response not json array you need to make following changes
JSONObject temp =new JSONObject(response);
JSONArray feedArray=temp.getJSONArray("items");

Try converting response string to JSONObject first
try{
JSONObject temp =new JSONObject(responseString); // response is a string
JSONArray feedArray=.getJSONArray("items");
....
}
You may try to use GSON library for parsing a JSON string. Here's an example how to use GSON,
Gson gson = new Gson(); // Or use new GsonBuilder().create();
MyType target = new MyType();
String json = gson.toJson(target); // serializes target to Json
MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2

Retrieve value from JSON responce

I am writing an android application and currently i am getting a JSON reply:
{"Error":"User already exists"}
this is an example of the messages that i get returned
the part that i am after is : "User already exists" and i need to parse it.
The message is currently stored in a string so i would need to convert this to a JSONArray to then convert it to a JSONOject to then be able to call the getString().
what would be the best way to do this?

this may Helps You
String Respones= "{\"Error\":\"User already exists\"}";
try {
JSONObject jobj = new JSONObject(Respones);
String strError = jobj.getString("Error");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

I think you can do it directly with JSONTokener and JSONObject if you want ot use default andoid tools.
If you want better, look into the Jackson lib, it's very powerful, open source, kind of standard:
Android JSON Jackson Tutorial

Try this code
JSONArray jsonArray = new JSONArray(ResponseString);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String result = jsonObject.getString("Error").toString().trim();
}

How to get json array values in android?

JSON response value looks like this "types" : [ "sublocality", "political" ]. How to get the first value of the types or how to get the word sublocality?

String string = yourjson;
JSONObject o = new JSONObject(yourjson);
JSONArray a = o.getJSONArray("types");
for (int i = 0; i < a.length(); i++) {
Log.d("Type", a.getString(i));
}
This would be correct if you were parsing only the line you provided above. Note that to access types from GoogleMaps geocode you should get an array of results, than address_components, then you can access object components.getJSONObject(index).
This is a simple implementation that parses only formatted_address - what I needed in my project.
private void parseJson(List<Address> address, int maxResults, byte[] data)
{
try {
String json = new String(data, "UTF-8");
JSONObject o = new JSONObject(json);
String status = o.getString("status");
if (status.equals(STATUS_OK)) {
JSONArray a = o.getJSONArray("results");
for (int i = 0; i < maxResults && i < a.length(); i++) {
Address current = new Address(Locale.getDefault());
JSONObject item = a.getJSONObject(i);
current.setFeatureName(item.getString("formatted_address"));
JSONObject location = item.getJSONObject("geometry")
.getJSONObject("location");
current.setLatitude(location.getDouble("lat"));
current.setLongitude(location.getDouble("lng"));
address.add(current);
}
}
catch (Throwable e) {
e.printStackTrace();
}
}

You should parse that JSON to get those values. You can either use JSONObject and JSONArray classes in Android or use a library like Google GSON to get the POJOs from JSON.

I would insist you to use GSON. I had created a demo for parsing the same map response. You can find the complete demo here. Also I had created a global GSON parser class that can be used to parse any response that is in JSON with ease.