Receiving Null while Parsing JSON

Question

Here is the response that I am receiving from my REST service from a GET Request:

{
  "type": "usersTable",
  "employeeId": 1,
  "employeeName": "Andrew Watson",
  "userPin": "705207"
}

I am trying to retrieve the userPin value from the JSON.

Here is the code I have attempted:

if (con.getResponseCode() == HttpsURLConnection.HTTP_OK 
           || con.getResponseCode() == HttpsURLConnection.HTTP_ACCEPTED ) {
    String line;
    BufferedReader br=new BufferedReader(new InputStreamReader(con.getInputStream()));
    while ((line=br.readLine()) != null) {
        JSONObject json = new JSONObject(br.toString());
        userPinRetrieved = String.valueOf(json.getInt("userPin"));
    }
}

Can anyone see why I am getting a Null Pointer?

@Lokesh I have seen this way used in other examples from this site.. should I be using something else? — AndroidBeginner2018, Jun 01 '18 at 09:35
@ThumChoonTat its not giving an error it is just getting null value — AndroidBeginner2018, Jun 01 '18 at 09:36
`json.getInt` on a String? Your `userPin` is a String not an int. — Ron Nabuurs, Jun 01 '18 at 09:36
is it weird that it is receiving null at runtime but receiving the correct value at debug? — AndroidBeginner2018, Jun 01 '18 at 09:58

Lokesh Pandey · Accepted Answer · 2018-06-01T10:03:42.380

1

I have not tested this one yet. But I think the problem is userPin is string not an integer value.

 if (con.getResponseCode() == HttpsURLConnection.HTTP_OK 
               || con.getResponseCode() == HttpsURLConnection.HTTP_ACCEPTED ) {
        String line;
        BufferedReader br=new BufferedReader(new InputStreamReader(con.getInputStream()));
        while ((line=br.readLine()) != null) {
            JSONObject json = new JSONObject(br.toString()); 
            if(json.getString("userPin") == null) {
               //do something here or define the default value
            }else {
                userPinRetrieved = json.getString("userPin");
            }
        }
    }

edited Jun 01 '18 at 10:03

answered Jun 01 '18 at 09:37

Lokesh Pandey

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is it weird that it is receiving null at runtime but receiving the correct value at debug? @Lokesh – AndroidBeginner2018 Jun 01 '18 at 09:58
can you check that your object's property "userPin" has got the pin value ? – Lokesh Pandey Jun 01 '18 at 09:59
@AndroidBeginner2018 I have update my answer. You can define a default value to the userPinRetrieved or do something else, if it's null. It should not throw exception this time – Lokesh Pandey Jun 01 '18 at 10:04
yes it is getting the correct pin value at debug mode. Although when I actually run the program it is getting null. very strange. – AndroidBeginner2018 Jun 01 '18 at 10:14
@AndroidBeginner2018 Can you try the updated answer ? And can you include the code why is it getting null ? I think the data you are receiving is having null values. If that is the case then you can avoid it using the updated answer – Lokesh Pandey Jun 01 '18 at 11:29
this was my problem: see also: https://stackoverflow.com/questions/50642036/asynctask-not-returning-result-quick-enough-to-main-thread – AndroidBeginner2018 Jun 01 '18 at 11:33
you may also like this one https://stackoverflow.com/questions/15635436/returning-data-from-asynctask-without-blocking-ui/15635493?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa – Lokesh Pandey Jun 01 '18 at 11:37

Receiving Null while Parsing JSON

1 Answers1