Parsing a JSON file in c# (Unity)

Question

I'm trying to parse a JSON file that I created from a JS app into Unity, in C#.

I have no experience with Json or reading data in general so I'm sure I'm missing something basic.

Here is how the data structure looks like in JS:

function DialIn () {
    this.id = null; this.line = "default in line"; this.links = [];
}

function DialOut () {
    this.id = null; this.line = "defauLt out line"; this.links = []; this.autoDelete = false;
}

function DialNode () {
    this.id = null; this.posX = null; this.posY = null; this.ins = []; this.outs = [];
}
            
var NodesDB = []; //DataBase of dial nodes

In a nutshell, NodesDB is an array of DialNode and each DialNode contains an array of ins and an array of outs.

Once store in a JSON, it looks like something like this (for example, with 3 nodes in NodesDB)

[{"id":"dn0","posX":82,"posY":234,"ins":[{"id":"dn0_in_0","line":"This is dynamic Blep ?","links":[]}],"outs":[{"id":"dn0_out_0","line":"Coucou, this is a reply.","links":["dn1_in_0"],"autoDelete":false}]},{"id":"dn1","posX":520,"posY":171,"ins":[{"id":"dn1_in_0","line":"This is dynamic Blep ?","links":["dn0_out_0"]}],"outs":[{"id":"dn1_out_0","line":"Coucou, this is a reply.","links":[],"autoDelete":false},{"id":"dn1_out_1","line":"Coucou, this is a reply.","links":["dn2_in_0"],"autoDelete":false}]},{"id":"dn2","posX":948,"posY":139,"ins":[{"id":"dn2_in_0","line":"This is dynamic Blep ?","links":["dn1_out_1"]}],"outs":[{"id":"dn2_out_0","line":"Coucou, this is a reply.","links":[],"autoDelete":false}]}]

Then, in Unity, I created this structure, trying to mimic the structures from JS:

    [System.Serializable]
    class DialIn
    {
        string id; string line; string[] links;
    }


    [System.Serializable]
    class DialOut
    {
        string id; string line; string[] links; bool autoDelete;
    }


    [System.Serializable]
    class DialNode
    {
        string id; int posX, posY; DialIn[] ins; DialOut[] outs;
    }

    DialNode[] NodesDB;

From there, I'm using these commands:

path = Application.dataPath + "/Jsons/Bloup.json";
jsonData = File.ReadAllText(path);

And I believe I should use something like this: NodesDB = JsonUtility.FromJson<DialNode>(jsonData);

But apparently, it's not that simple.

Any help would be greatly appreciated :o

I have created a much simpler version of my script without the arrays of arrays and all that noise. The FromJson is working well in that case. I think the problem is that my Json doesn't contain a class but an array of said class. I haven't found a workaround,though. I'm looking into this: answers.unity.com/questions/1123326/… — Ezhaac
– Ezhaac, Commented Oct 18, 2020 at 15:40

frankhermes - Stop OpenAI · Accepted Answer · 2020-10-18 11:53:26Z

4

Make all your object's member variables public. JSONUtility doesn't (de)serialize private member variables.
See the documentation.

Alternatively if you really want your member variables private, add the [SerializeField] attribute to every field you want serialized.

answered Oct 18, 2020 at 11:53

frankhermes - Stop OpenAI

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4 Comments

Ezhaac Over a year ago

I've made all of my classes and NodesDB public but there is still a few things wrong. This is where I want to put my data: public DialNode[] NodesDB; But when I use the command NodesDB = JsonUtility.FromJson<DialNode>(nodesData); I get an error "Cannot implicitly convert type DialNode to DialNode[]" I don't see how to deal with the array, but I'm not even sure I get the syntax right, with the FromJson.

Ezhaac Over a year ago

I can work around the error using NodesDB = JsonUtility.FromJson<DialNode[]>(nodesData); but then, I get: "ArgumentException: JSON must represent an object type."

frankhermes - Stop OpenAI Over a year ago

I guess you need another class to wrap around your nodes array, and your json should not start with an array as the root, but should look like this: { "nodesDB":[{...},{...},etc]}. Does that help?

Ezhaac Over a year ago

It does! I've been reading that Unity's parser is not supporting arrays at the root of the json file. I guess once the data is extracted, I can get rid of this 'container' and there we go =)

hossein bazee · Accepted Answer · 2020-10-19 11:10:29Z

1

you can add simple json to your project and them using on your top script, I use this Script for parse and other...

 var N = JSON.Parse(the_JSON_string);
 var versionString = N[0]["id"].Value;  
 var versionString = N[0]["posX"].Value;

and other ....

answered Oct 19, 2020 at 11:10

hossein bazee

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