Android: converting JSONObject to JSONArray returns null

Question

My code:

JSONObject data = {"result":{"a":[{"artist":"Aney","number:"1"},{"artist":"Aney","number:"2"}],"b":[{"artist":"Boney","number:"3"},{"artist":"Boney","number:"4"}], ....
JSONObject obj = new JSONObject(data.toString());
JSONArray tasks = obj.optJSONArray("result");

But tasks returns null.

I tried the below code but it did not work:

JSONObject data = {"result":{"a":[{"artist":"Money",...
JSONArray tasks = data.optJSONArray("result");

Update :

My main code is :

// get data from main url and reutnr array
JSONArray tasks = data.optJSONArray("result");
if(alert){
    // get data from another url and return object
    JSONObject data = {"result":{"a":[{"artist":"Money",...
    tasks = data.optJSONArray("result");
}

// now i use tasks in my code
if(tasks.length() > 0){
    ....
}

[This post](https://stackoverflow.com/questions/22687771/how-to-convert-jsonobjects-to-jsonarray) might be useful. — 0xCursor, Jul 04 '18 at 20:54
@LAD thank you. but my json code have very key and value. this is take time — salari mameri, Jul 04 '18 at 21:01
then you have to parse it as an object and then go through each property adding to an array so that you get the structure you want — geekley, Jul 04 '18 at 21:14
you should give an example with the value you would epect when you call `tasks = data.optJSONArray("result")`. Also, what is the structure of `"result"`? Does it have "a", "b", and so on? Or is it a single "a" field with the array you want? — geekley, Jul 04 '18 at 21:20

score 1 · Accepted Answer · answered Jul 04 '18 at 20:52

1

When you see "key": { ... }, that means key is a JSONObject.

When you see "key": [ ... ], that means key is a JSONArray.

In your case, "result" is a JSONObject, so write this instead:

JSONObject tasks = obj.optJSONObject("result");

answered Jul 04 '18 at 20:52

Ben P.

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@salarimameri well, the `results` object **isn't** an array, so you're going to have to clarify what you mean. – Ben P. Jul 04 '18 at 21:06

score 0 · Answer 2 · answered Jul 04 '18 at 21:11

The JSONArray (a, b) is inside the object 'result' inside of the root object so you have to navigate the hyerarchy to get it:

JSONObject obj = new JSONObject(data.toString());
JSONObject result = obj.getJSONObject("result");
JSONArray tasksA = result.optJSONArray("a");
JSONArray tasksB = result.optJSONArray("b");

Note that each 'a' and 'b' is a different JSONArray to be retrieved.

Android: converting JSONObject to JSONArray returns null

2 Answers2