Develop Reference

Why I am getting null JSON response?

I am fetching data from JSON to android.But, I am getting an empty JSON response. The PHP code which generates JSON data is as follows:
$result = $conn->query("SELECT dbname FROM users ORDER BY dbname ASC");
//defined second array for dbnames' list
$dblist = array();
while($row = $result->fetch_assoc()){
//array_push($response['dblist'],$row['dbname']);
$dblist[] = array('name'=>$row['dbname']);
}
$response['dblist'] = $dblist;
This is the JSON response.
{"dblist":[{"name":"a"},{"name":"arsod"}]}
The Java code to fetch data in android is as follows:
JSONObject obj = new JSONObject(s);
JSONArray names = obj.getJSONArray("dblist");
for(int i=0; i < names.length(); i++) {
JSONObject n = names.getJSONObject(i);
String name = n.getString("name");
Toast.makeText(MainActivity.this, name, Toast.LENGTH_SHORT).show();
institutes.add(name);
}
where institutes is an ArrayList in which I want to add each fetched element. But while fetching the data, I get the error in logcat org.json.JSONException: End of input at character 0 of. What is going wrong?

Considering the following:
s = {"dblist":[{"name":"a"},{"name":"arsod"}]}
Your code should be like,
JSONObject obj = new JSONObject(s);
JSONArray names = obj.getJSONArray("dblist");
for(int i=0; i < names.length(); i++) {
JSONObject n = names.getJSONObject(i);
String name = n.getString("name");
Toast.makeText(MainActivity.this, name, Toast.LENGTH_SHORT).show();
institutes.add(name);
}

remove this line:
JSONObject object = obj.getJSONObject("dblist");
and replace all occurences of object. with obj.
your JSONObject obj doesn't contain "dblist" object, there is only array inside it, so you should look for getJSONArray("dblist") straight inside obj
edit: you are parsing different String s, I've just checked this code:
final String s = "{\"dblist\":[{\"name\":\"a\"},{\"name\":\"arsod\"}]}";
JSONObject obj = new JSONObject(s);
JSONArray names = obj.getJSONArray("dblist");
for (int i = 0; i < names.length(); i++) {
JSONObject n = names.getJSONObject(i);
String name = n.getString("name");
Toast.makeText(this, name, Toast.LENGTH_SHORT).show();
}
which is almost exacly same as your and works pretty fine...

How can I put JSON return in an array?

I'm a android beginner and I'm doing to access a JSON file in and it has an error. I have a problem in parsing this
JSONObject jsonObject = new JSONObject(jsonStr);
JSONArray accounts = jsonObject.getJSONArray("account_data");
for(int i=0;i < accounts.length();i++){
JSONObject a = accounts.getJSONObject(i);
sin = a.getString("sin");
account_name = a.getString("account_name");
address = a.getString("address");
status = a.getString("status");
due_date = a.getString("due_date");
total_amount = a.getDouble("total_amount");
sin_lbl.setText(a.getString("account_name"));
}
here is the JSON File
{"account_data":{
"sin":"200111-102 ",
"account_name":"LUMABAN, CRISTOM ",
"address":"352 MABINI ST.,, SABANG, Baliwag ",
"status":"A ",
"due_date":"2019-04-23",
"total_amount":"491.00"
},"code":1101,"message":"Account Info Retrieved"}
I have an error in putting it in array.

Instead of using JSONArray , try to use JSONObject.
String[] array = {json.get("sin"), json.get("account_name"), json.get("address"), json.get("status"), json.get("due_date"), json.get("total_amount") }

{"account_data":{"sin":"200111-102 ","account_name":"LUMABAN, CRISTOM ","address":"352 MABINI ST.,, SABANG, Baliwag ","status":"A ","due_date":"2019-04-23","total_amount":"491.00"},"code":1101,"message":"Account Info Retrieved"}
Actually, it's a json object, not array. So that you can not convert json object to json array
Difference between Json Array and Json Object:
A JSONArray is an ordered sequence of values. A JSONObject is an unordered collection of name/value pairs.
JSONArray: Its external text form is a string wrapped in square brackets with commas separating the values.
JSONObject: Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names.

Please use this json parshing
try {
JSONObject jsonObject = new JSONObject(jsonStr);
JSONObject accounts = jsonObject.getJSONObject("account_data");
sin = accounts.getString("sin");
account_name = accounts.getString("account_name");
address = accounts.getString("address");
status = accounts.getString("status");
due_date = accounts.getString("due_date");
total_amount = accounts.getDouble("total_amount");
sin_lbl.setText(a.getString("account_name"));
} catch (Exception e) {
}

if you asked about iterating on json object you could try this one
JSONObject jObject = new JSONObject(jsonStr);
JSONObject menu = jObject.getJSONObject("account_data");
Map<String,String> map = new HashMap<String,String>();
Iterator iter = menu.keys();
while(iter.hasNext()){
String key = (String)iter.next();
String value = menu.getString(key);
map.put(key,value);
}
so now you have your data into as pair of key and value
if you have a json array of this response you could do as following
JSONObject root = new JSONObject("your root");
JSONArray resultArray = root.getJSONArray("your array key");
for (int i = 0; i < resultArray.length(); i++) {
// here to get json object one by one and access every item into it
JSONObject resultObject = resultArray.getJSONObject(i);
posterPath = resultObject.getString("key");
title = resultObject.getString("key");
releaseDate = resultObject.getString("key");
description = resultObject.getString("key");
voteAverage = resultObject.getDouble("key");
}

Parsing json code to a string in android using volley

i need help to parse this json code to actual strings using android volley. this is the json code:[{"name":"Tayo","0":"Tayo","thread_name":"Welcome","1":"Welcome","post":"Hi there,","2":"Hi there,","post_time":"Sunday","3":"Sunday"},{"name":"Pete","0":"Pete","thread_name":"Welcome","1":"Welcome","post":"Hi,am pete","2":"Hi,am pete","post_time":"Monday","3":"Monday"}].
I have tried other helps but not working. Thanks!

Remember:
if the .json content starts with { is considered as a Json Object.
if the .json content starts with [ is considered as a Json Array.
so you hava a JsonArray then you can parse your content like this way:
//Obtain the JsonArray
JSONArray jsonArray = new JSONArray(myJsonContent);
// Get the JsonObjects inside JsonArray
for(int i=0;i<jsonArray.length();i++){
JSONObject jsonobject = jsonArray.getJSONObject(i);
}

// strData is the json data received.
JSONArray jsonArray = new JSONArray(strData);
for (int i=0; i<jsonArray.length();i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
String name = jsonObject.optString("name");
String zero = jsonObject.optString("0");
String thread_name = jsonObject.optString("thread_name");
String one = jsonObject.optString("1");
String post = jsonObject.optString("post");
String two = jsonObject.optString("2");
String post_time = jsonObject.optString("post_time");
String three = jsonObject.optString("3");
//Just an example
arrayName.add(jsonObject.optString("name"));
}
You can even use array to store data instead of the string.

How to parse json response in android which is of the following format

I am trying to parse a json response in android for my android application. I am getting org.json.JSONException. The response is as shown below:
{
id: "12345"
email:"abc#gmail.com"
firstName:"abcd"
lastName:"efgh"
userName:"abc123"
}
I am trying to parse the response as shown below:
if (response != null) {
try {
//JSONObject jsonObj = new JSONObject(text);
// Getting JSON Array node
JSONArray contacts = new JSONArray(response.toString());
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
id = c.getString("_id");
email = c.getString("email");
firstName = c.getString("firstName");
lastName = c.getString("lastName");
userName = c.getString("userName");
}
} catch (JSONException e) {
e.printStackTrace();
}
Can any one let me know what mistake am I doing in parsing the response. All suggestions are welcome.

Simply replace this you are using "_id" instead of "id"
id = c.getString("id");
email = c.getString("email");
firstName = c.getString("firstName");
lastName = c.getString("lastName");
userName = c.getString("userName");

Change this id = c.getString("_id"); to id = c.getString("id");
in the future, you may show error in logcat when parsing like this:
catch (JSONException e) {
e.printStackTrace();
Log.e("TAG", e.getMessage());
}

There are two things I can think of , first of all you should get to know that what are [] , {} . The square brackets are arrays in json and curly demonstrate the object , so I think you are casting it wrong
1>
JSONArray contacts = new JSONArray(response.toString()); "this is culprit"
You should change it to
JSONObject. Use JSONObject in place of JSONArray
and Secondly
2> change this key id = c.getString("_id");to
id = c.getString("id");
Make sure You are getting and writing spellings of all keys right else it would generate exception.

JSONObject Android failed to create

I have GetRequest and as a response I got HTML head and the content of body element is Array of JSONS. Iam unable to parse it, could anyone post a tip how to create JSON Object from this response??

If you have your JSON return value in String json you can do
JSONArray a = new JSONArray(json);
The first JSONObject in the array can then be retrieved with
JSONObject o = a.getJSONObject(0);

You can create a JSON Object from a string like this.
String myString = "This is the response from your HTTP GET request";
JSONObject myJson = new JSONObject(myString);
Note that the value of myString must be valid JSON.

My problem was, when I downloaded request from server I have to get only content of element. Than I used standard JSONArray and everything is working fine.

// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
contacts = json.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for(int i = 0; i < contacts.length(); i++){
JSONObject c = contacts.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_ADDRESS);
String gender = c.getString(TAG_GENDER);
// Phone number is agin JSON Object
JSONObject phone = c.getJSONObject(TAG_PHONE);
String mobile = phone.getString(TAG_PHONE_MOBILE);
String home = phone.getString(TAG_PHONE_HOME);
String office = phone.getString(TAG_PHONE_OFFICE);
}
} catch (JSONException e) {
e.printStackTrace();
}