Parsing JSON response when returned as Array

Question

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $

This is the error I continue to get while attempting to parse my incoming JSON response data. I'm utilizing the OkHttp library to create and call, and the API I'm getting results from returns everything in an Array as follows:

    [
      {
        "id": 4256,
        "image_url": "https://cdn.pandascore.co/images/league/image/4256/OMEN_Challenger_Series_2019.png",
        "live_supported": false,
        "modified_at": "2019-10-30T10:02:42Z",
        "name": "OMEN Challenger",
        "series": [
          {
            "begin_at": "2019-11-01T03:30:00Z",
            "description": null,
            "end_at": null,
            "full_name": "2019",
            "id": 1932,
            "league_id": 4256,
            "modified_at": "2019-10-30T09:11:40Z",
            "name": null,
            "prizepool": "50000 United States Dollar",
            "season": null,
            "slug": "cs-go-omen-challenger-2019",
            "winner_id": null,
            "winner_type": null,
            "year": 2019
          }
        ],
        "slug": "cs-go-omen-challenger",
        "url": "https://omengaming.co/omen_cs/",
        "videogame": {
          "current_version": null,
          "id": 3,
          "name": "CS:GO",
          "slug": "cs-go"
        }
      },
      {...},
      {...},
      {...},
      {...},
    ]

I found a lot of folks recommending Gson to parse it into a custom class, but the following code, in theory, should work and it isn't. The parsing doesn't even begin due to it expecting BEGIN_OBJECT and it being BEGIN_ARRAY:

String jsonData = response.body().string();
Gson gson = new Gson();
EventInfo test = gson.fromJson(jsonData, EventInfo.class);

class EventInfo {

    String imageURL;
    String name;
    JSONArray series;

}

Answer 1

So, I figured it out. Originally I was receiving the same error at a later point; namely when it got to the series key value in the first JSONObject. The original error occurred because I was trying to parse series as a JSONArray, rather than a List<JSONObject> The corrections are below:

String jsonData = response.body().string();
Gson gson = new Gson();
Type listType = new TypeToken<List<EventInfo>>() {}.getType();
List<EventInfo> test = gson.fromJson(jsonData, listType);

And the EventInfo class:

class EventInfo {

    String imageURL;
    String name;
    List<JSONObject> series;

}

Thank you for the advice everyone!

Answer 2

You are trying to parse it into an object. But in your response, you can clearly see that it's a list. The parent POJO should have been a list. And inside that list, you should have created another POJO.

Answer 3

In your response parent is found as array but you need to add first parent as JSON object and child as a array or object.

You need response like this

{
    "YourArrayName":[
        "YourChildObjName":{
            "id": 4256,
            "image_url": "https://cdn.pandascore.co/images/league/image/4256/OMEN_Challenger_Series_2019.png",
            "live_supported": false,
            "modified_at": "2019-10-30T10:02:42Z",
            "name": "OMEN Challenger",
            "series": [
                {
                    "begin_at": "2019-11-01T03:30:00Z",
                    "description": null,
                    "end_at": null,
                    "full_name": "2019",
                    "id": 1932,
                    "league_id": 4256,
                    "modified_at": "2019-10-30T09:11:40Z",
                    "name": null,
                    "prizepool": "50000 United States Dollar",
                    "season": null,
                    "slug": "cs-go-omen-challenger-2019",
                    "winner_id": null,
                    "winner_type": null,
                    "year": 2019
                }
            ],
            "slug": "cs-go-omen-challenger",
            "url": "https://omengaming.co/omen_cs/",
            "videogame": {
                "current_version": null,
                "id": 3,
                "name": "CS:GO",
                "slug": "cs-go"
            }
        },
        {...},
        {...},
        {...},
        {...},
    ]
}

I hope this can help You!

Thank You