How to remove nested field of Json object using Gson

Question

My JSON response:

{
    "date": 1555044585641,
    "changed": true,
    "data": {
        "items": [
            {
               "id": 503,
                "activated": false,
                "view": {
                    "listItem": {
                        ...
                    },
                    "details": {
                        ...
                    }
                }       
            }
        ]
    }
}

I am using below class to parse JSON using Gson :

public class Response {

    @SerializedName("date")
    public long date;

    @SerializedName("changed")
    public boolean changed;

    @SerializedName("data")
    public JsonObject data;
}

I save "data" part as a string using data.toString() since data is JsonObject . My question is:

How can I exclude "details" part before saving?

Saved string should look like:

{
    "items": [
        {
           "id": 503,
            "activated": false,
            "view": {
                "listItem": {
                    ...
                }
            }       
        }
    ]
}

Answer 1

You need to traverse JSON structure using JsonElement , JsonArray , JsonObject :

class Response {

    @SerializedName("date")
    public long date;

    @SerializedName("changed")
    public boolean changed;

    @SerializedName("data")
    public JsonObject data;

    public void removeDetails() {
        JsonElement items = data.get("items");
        if (!items.isJsonArray()) {
            return;
        }
        JsonArray array = items.getAsJsonArray();
        array.forEach(item -> {
            if (item.isJsonObject()) {
                JsonObject node = item.getAsJsonObject();
                JsonElement view = node.get("view");
                if (view.isJsonObject()) {
                    view.getAsJsonObject().remove("details");
                }
            }
        });
    }
}

After deserialisation invoke removeDetails() and you can save only required data.