How can I control a empty JsonArray, if string is " [ ] "

Question

my json string is

String RESPONSE = "  { "Table": [] }  ";

and I use

 JSONObject jsonObj = new JSONObject(RESPONSE);
 JSONArray contacts = jsonObj.getJSONArray("Table");

Therefore, contacts = [] I mean empty. How can I control that array is empty. After this controller I use this command

JSONObject c = contacts.getJSONObject(0);

Of course is not empty :)

What do you mean "Of course is not empty"? Did you put something in it after your previous code where you obtained a clearly empty array? — azurefrog, Mar 13 '17 at 17:57

score 1 · Answer 1 · answered Mar 13 '17 at 17:58

1

You can use length function:

JSONObject jsonObj = new JSONObject(RESPONSE);
JSONArray contacts = jsonObj.getJSONArray("Table");
if(contacts.length() > 0 ) {
    JSONObject c = contacts.getJSONObject(0);
}

answered Mar 13 '17 at 17:58

Veneet Reddy

2,707
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I've tried. Not working – Sefa Taşcan Mar 13 '17 at 18:02
what was happening, were you getting some error? – Veneet Reddy Mar 13 '17 at 18:08

Dec · Answer 2 · 2017-03-13T18:07:23.847

1

You could use the isNull() function.

JSONObject jsonObj = new JSONObject(RESPONSE);
JSONArray contacts = jsonObj.getJSONArray("Table");
if(!contacts.isNull(0)) {
   JSONObject c = contacts.getJSONObject(0);
}

edited Mar 13 '17 at 18:07

answered Mar 13 '17 at 18:01

Dec

203
2
11

No such function – Sefa Taşcan Mar 13 '17 at 18:04
Correct. Edited to show isNull. – Dec Mar 13 '17 at 18:07
No, Not working – Sefa Taşcan Mar 13 '17 at 18:16
contacts = " [ ] " ; – Sefa Taşcan Mar 13 '17 at 18:17
Have I miss understood the question? What do you mean by not working? are you saying contacts[0] is empty yet the if statement is still executing? – Dec Mar 13 '17 at 18:19
contacts has a string that is " [ ] ", but I want to assume empty – Sefa Taşcan Mar 13 '17 at 18:22
be careful Response is { "Table": [] } – Sefa Taşcan Mar 13 '17 at 18:23
Try checking if the array is not null and the length is greater than 0. Try: if(contacts != null && contacts.length() > 0) – Dec Mar 13 '17 at 18:29
I tried man. but not working – Sefa Taşcan Mar 13 '17 at 20:00
Works at this end, but maybe I don't understand what you're trying to achieve. – Dec Mar 13 '17 at 20:05
1

Worked for me, thanks! – GiovanyMoreno Jul 09 '19 at 00:00

How can I control a empty JsonArray, if string is " [ ] "

2 Answers2