How to assign JSONArray to variable?

Question

I'm new to Java and I have a problem :

JSONObject data = new JSONObject(json);
List<String> list = (List<String>) data.getJSONArray("childrens");

for (String item : list) {
       Log.d("DEBUG", item);
}

I would like to assign data.getJSONArray("childrens") to a variable list, but I have an error:

java.lang.ClassCastException: org.json.JSONArray cannot be cast to java.util.List

How can I do this?

I would like to iterate over JSON Array.

The error tells you exactly what the problem is, that the method .getJSONArray(...) returns an org.json.JSONArray object, not a java.util.List object, and casting the thing won't fix this. You need to create a JSONArray variable, assign to it the object returned from the method, and then use methods available to this object. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Jun 17, 2018 at 18:03
The JSONArray API will tell you what methods you can use with this, but I'd look at using the length() and get(int index) methods to iterate through using a for loop. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Jun 17, 2018 at 18:04

victor gallet · Accepted Answer · 2018-06-17 18:05:55Z

3

You can't data.getJSONArray("childrens") returns an object of type org.json.JSONArray.

However, you can iterate over a JSONArray :

    JSONArray jArray = data.getJSONArray("childrens");

    for (int i = 0; i < jArray.length(); i++) {
        JSONObject jb = jArray.getJSONObject(i);
        Log.d("DEBUG", jb);
    }

answered Jun 17, 2018 at 18:05

victor gallet

1,89818 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Luiggi Mendoza · Accepted Answer · 2018-06-17 18:06:39Z

1

JSONObject only contains JSONArray, not List. You have to transform it manually:

JSONObject data = new JSONObject(json);
JSONArray jsonArray = data.getJSONArray("childrens");
for (Object o : jsonArray) {
    String child = (String)o;
    Log.d("DEBUG", child);
}

answered Jun 17, 2018 at 18:06

Luiggi Mendoza

85.9k16 gold badges160 silver badges355 bronze badges

1 Comment

Luiggi Mendoza Over a year ago

@HovercraftFullOfEels documentation states it for latest version on 2016.

Collectives™ on Stack Overflow

How to assign JSONArray to variable?

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related