Conversion Casting Issues

Question

I am developing a small side scroller game using slick 2D lwjgl and am running into a current error while casting something.

It seems to be not recognizing that i'm casting the json string as a JsonArray.

The error and the function,

java.lang.ClassCastException: java.lang.String cannot be cast to org.json.simple.JSONArray
    at world.World.load(World.java:35)
    at game.Engine.initStatesList(Engine.java:64)
    at org.newdawn.slick.state.StateBasedGame.init(StateBasedGame.java:164)

function:

public static void load(String path) throws Exception
{
    JSONParser parser = new JSONParser();
    Object obj = parser.parse(new FileReader(path));
    JSONObject jSonOBJ = (JSONObject)obj;

    JSONArray layers = (JSONArray)jSonOBJ.get("layers");
    int amount = layers.size();

    for (int i = 0; i < amount; ++i)
    {
        JSONObject layer = (JSONObject) layers.get(i);
        String type = (String)layer.get("name");

        if (type.equals("solids"))
        {
            solids = parse((JSONArray)layer.get("data")); //error
        }
        else if (type.equals("spawns"))
        {
            //to-do
        }
    }
}

this is just to parse if the json, my map, tile is a solid or not, but I have been stuck on this small error for a little time. the line of code solids = parse((JSONArray)layer.get("data")); should convert it to JSONArray correct?

score 0 · Answer 1 · edited May 23 '17 at 11:59

0

There is a lot of way to get Object to prevent you from casting everytime. The method getJSONArray will allow you to have directly a JSONArray.

Here is an example taken from this post:

JSONObject jsnobject = new JSONObject(yourString);
JSONArray jsonArray = jsnobject.getJSONArray("nameOfArrayAttribute");
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject explrObject = jsonArray.getJSONObject(i);
}

Here you see that you just have to buil your Json Object from your String. Then you can extract your document with specific method to get strong typed object.

edited May 23 '17 at 11:59

Community

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answered Dec 04 '15 at 08:01

RPresle

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Still having trouble with this, `Image[][] solids` is my 2D array of Images. I am simply calling, `solids = ` then parsing, `parse((JSONArray)layer` layer is a JSONObject containing one of the indices of solids, `.get("data")` .get to receive the 2d array via the key "data" thats found inside the layers object on my JSON request – SenjuXo Dec 04 '15 at 16:47
Can you provide your JSON text please? And have you tried skipping the cast and calling `solids = layer.getJSONArray("data");` – RPresle Dec 07 '15 at 08:12

Conversion Casting Issues

1 Answers1