Kotlin JSONArray to MutableList<JSONObject>

Question

I am fairly new to Kotlin and I am currently dealing with JSON a lot.

I receive a JSON string from the server which I parse into JSONArray as below

var dataArray = JSONArray(String(resultVar!!))

But as far as I've seen JSONArray doesn't really give me enough capabilities to change it's data, it forces me to create a new JSONArray, if I'm not mistaken. So I thought I should use MutableList<JSONObject>, which seems good enough, but I can't find a way to parse JSONArray or the String into it.

How do I do this the easy way? Do I have to iterate through the JSONArray adding every single JSONObject one by one?

As a side question, should I just stick to JSONArray? Is there a way to manipulate the data inside it?

Yoav Sternberg · Accepted Answer · 2020-06-06 17:48:13Z

6

As far as it seems, there is no builtin method to convert JSONArray to List. However, You can use Kotlin tricks to make the java code much shorter:

fun JSONArray.toMutableList(): MutableList<JSONObject> = MutableList(length(), this::getJSONObject)

Note that JSONArray may have values that are not JSONObject (but JSONArray for example). If you are not sure the array contains just object, use the following method:

fun JSONArray.toMutableList(): MutableList<Any> = MutableList(length(), this::get)

If you are using the JSON-java library and not the android one, then you can use JSONArray.toList() which returns a list you can modify.

edited Jun 6, 2020 at 17:48

answered Nov 11, 2018 at 18:33

Yoav Sternberg

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1 Comment

Aegletes Over a year ago

Thanks a lot for this!

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