How to load an array with JsonUtility?

I have a json array like this:

Code (CSharp):

1. [
2.     {
3.         "key": "here's the key",
4.     },
5.     {
6.         "key": "here's the key",
7.     }
8. ]

I try to load like this:

Code (CSharp):

1. [Serializable]
2. public class Info
3. {
4.     public string key;
5. }
6.  
7. var asset = Resources.Load<TextAsset>("JsonTest");
8. var info = JsonUtility.FromJson<Info[]>(asset.text);

But it says like this:

 

Did you make the json yourself?

 

yes

 

is asset null by any chance?

 

Nope

 

try inheriting from System.Object

 

Nothing different. If I print .Lenght it says 174090232

 

change var asset=Resources.Load<TextAsset>("JsonTest");
to
var asset=Resources.Load<TextAsset>("JsonTest.json");

 

Thanks for the instructions Richard, Can you give an example on how to retrieve value for individual key such that a row has more than one key and its respective values. ?

Ex :
{
"object":
{
"name": "nm",
"place": "plc",
"description": "dscrptn",
},
{
"name": "nm",
"place": "plc",
"description": "dscrptn",
},
{
"name": "nm",
"place": "plc",
"description": "dscrptn",
},
etc
}
How to access each values or say in a loop or something like that ?

 

I made this helper method to wrap a json around a class, this way you don't need to change code on the server for accommodating the json top-level array problem .

Code (CSharp):

1.     public static string WrapToClass(this string source, string topClass){
2.         return string.Format("{{ \"{0}\": {1}}}", topClass, source);
3.     }

 

Took me a while to notice that FromJson doesn't work if the class members are defined as properties

 

I wrote a little workaround:

Code (CSharp):

1. public class JsonHelper
2. {
3.     public static T[] getJsonArray<T>(string json)
4.     {
5.         string newJson = "{ \"array\": " + json + "}";
6.         Wrapper<T> wrapper = JsonUtility.FromJson<Wrapper<T>> (newJson);
7.         return wrapper.array;
8.     }
9.  
10.     [Serializable]
11.     private class Wrapper<T>
12.     {
13.         public T[] array;
14.     }
15. }

You can now simple deserialize like this:

Code (CSharp):

1. YouObject[] objects = JsonHelper.getJsonArray<YouObject> (jsonString);

Very surprising a such basic feature is not implemented...

 

This worked beautifully! Thanks ffleurey

 

Hi, this helped a lot. Thank you!

 

Hi,
I'm trying this answer, but have doubts about how to properly set YouObject[]?
Thanks for the help

 

JSON Utility class doesn't support Array types or List yet?

I'm trying something like this to use Lists and seems to work well, but i'm not sure if is a good implementation:

Code (CSharp):

1. [System.Serializable]
2. public class PlayerStats{
3.  
4. public int life;
5. public string name;
6. public int energy;
7. }

Then,

Code (CSharp):

1. [System.Serializable]
2. public class PlayerStatsList {
3.  
4.     public List <PlayerStats> playerStats;
5. }

Now, in the class that i wan't to access to the JSON File:

Code (CSharp):

1. public PlayerStatsList myPlayerStatsList = new PlayerStatsList();
2.  
3. JsonUtility.FromJsonOverwrite (jsonText, myPlayerStatsList);
4.  

With this, i have all the info loaded from the JSON file in the list myPlayerStatsList.playerStats.

The JSON File must have the same structure that the PlayerStats class, like this:

Code (CSharp):

1. {
2.     "PlayerStats": [
3.         {
4.             "life": "10",
5.             "name": "Kratos",
6.             "energy": 100
7.         },
8.         {
9.             "life": "80",
10.             "name": "Nathan",
11.             "energy": 20
12.         },
13.         {
14.             "life": "90",
15.             "name": "Link",
16.             "energy": 25
17.         }
18.     ]
19. }

 

Simple and clever, Thanks !

 

If you use this free Unity-compatible fork of Newtonsoft's JSON.NET, then everything just works as you'd expect. There's a good reason even Microsoft recommends using this third-party solution rather than .NET's built-in options!

https://github.com/SaladLab/Json.Net.Unity3D

Code (csharp):

1. PlayerStats[] statArray = JsonConvert.DeserializeObject<PlayerStats[]>(json);

 

Is it working ?
Its not Working for me :/

 

Thanks, it work!!!!

 

It's helpful, but how to make a file like ur file [PlayerStats].

 

hey everyone! - i'm having a bit of trouble on the deserializing front. here's the basic array format in text file. note that my code doesn't contain the indents or line breaks - i assume that's not important? i'm breaking it up here so you can see the basic structure:

Code (JavaScript):

1.  
2. {
3. "SavedLayer":[
4. {
5. "layerName":"Layer_0",
6. "instrumentNumber":0,
7. "seqLength":7,
8. "timeDivision":8,
9. "gateTime":0.30000001192092898,
10. "noteRowAssign":[30,42,44,46,47,59,63,80]
11. },
12. {"layerName":"Layer_1",
13. "instrumentNumber":1,
14. "seqLength":8,
15. "timeDivision":16,
16. "gateTime":0.30000001192092898,
17. "noteRowAssign":[40,42,43,44,46,48,49,51]
18. },
19. ]
20.  
21. }

i'm trying to retrieve it like this:

Code (CSharp):

1.  
2. string AllTheData=File.ReadAllText(filename);
3. SavedLayer[] data=JsonHelper.getJsonArray<SavedLayer>(AllTheData);
4. Debug.Log(data[0]);

SavedLayer is the basic class i created to store each object's data in JSON. it validates in JSON Lint as well. however if i try to get the first object in the array using this method, i get 'unexpected node type' and a Null Ref on the Debug.Log statement.

any clue what i'm doing wrong here?

 

hmm - well looking at it after some sleep it actually looks like it wraps the '['and ']' that begin and end the array with '{ array:' and '}'. which technically means i don't have to bother as long as my array begins and ends with square brackets. but i'm still having a lot of trouble understanding the deserialization process. i went back to the Scripting API for retrieving JSON data (https://docs.unity3d.com/ScriptReference/JsonUtility.FromJson.html). i've given it a try, but my code is definitely not working. the main bit is here:

Code (CSharp):

1.     public static DataManager.SavedLayer readLayerJSON(string dataString)
2.     {
3.         string AllTheData = File.ReadAllText(DataManager.filenamePath());
4.         allLayers = JsonHelper.getJsonArray<DataManager.SavedLayer>(AllTheData);
5.  
6.         for (int count=0; count <8; count++)
7.         {
8.             return JsonUtility.FromJson<DataManager.SavedLayer>(dataString);
9.         }
10.  
11.     }

i'm obviously getting confused about what all the data(aka AllTheData) is vs parsing out each individual JSON object within the data. is it possible to retrieve all data for all objects at once without having to loop? this code fails but all my fixes so far aren't doing the trick. i want to copy each Layer object's JSON data to each element of allLayers, which is an array of DataManager.SavedLayer classes. assistance appreciated!

 

ADD THAT INTO DOCUMENTATION !!!!

There is no mention about properties in docs. So you can save developers' time and Karma of unitech

 

It works like charm ,man (Y) hope it wouldn't fail in any case Thanku

 

hey, I just want to refer this issue to this thread, but I have an issue on hololens with it.
https://forum.unity3d.com/threads/json-top-level.461322/#post-2997068

Anyway thx ffleure -> good job

 

I use both SimpleJson and JsonUtility

 

You're an HERO elektronische!
I confirm this works just fine and using lists instead of arrays brings only advantages to me!

This is how the official unity documentation should look like:

JsonUtility

class in UnityEngine

Other Versions


Description
Utility functions for working with JSON data.
YO FOLKS, arrays DO NOT work with this utility!!! Just use Lists and FromJsonOverwrite to store lists of data.

 

Absolutely right^

However, if you do need/want to use arrays and don't want to/can change the response from the server you could just wrap your json array inside an object. Then you can use the Wrapper<T> method discussed before.

So if you have this:

Code (JavaScript):

1. [
2.     {
3.         "id": "1",
4.         "name": "foo"
5.     },
6.     {
7.         "id": "2",
8.         "name": "bar"
9.     },
10.     {
11.         "id": "3",
12.         "name": "baz"
13.     }
14. ]

You want to get something like this:

Code (JavaScript):

1. {
2.     "items": [
3.         {
4.             "id": "1",
5.             "name": "foo"
6.         },
7.         {
8.             "id": "2",
9.             "name": "bar"
10.         },
11.         {
12.             "id": "3",
13.             "name": "baz"
14.         }
15.     ]
16. }

Here's my updated JsonHelper.cs https://gist.github.com/halzate93/77e2011123b6af2541074e2a9edd5fc0

Code (CSharp):

1. using System;
2. using UnityEngine;
3.  
4.     public static class JsonHelper
5.     {
6.         public static T[] FromJson<T>(string jsonArray)
7.         {
8.             jsonArray = WrapArray (jsonArray);
9.             return FromJsonWrapped<T> (jsonArray);
10.         }
11.  
12.         public static T[] FromJsonWrapped<T> (string jsonObject)
13.         {
14.             Wrapper<T> wrapper = JsonUtility.FromJson<Wrapper<T>>(jsonObject);
15.             return wrapper.items;
16.         }
17.  
18.         private static string WrapArray (string jsonArray)
19.         {
20.             return "{ \"items\": " + jsonArray + "}";
21.         }
22.  
23.         public static string ToJson<T>(T[] array)
24.         {
25.             Wrapper<T> wrapper = new Wrapper<T>();
26.             wrapper.items = array;
27.             return JsonUtility.ToJson(wrapper);
28.         }
29.  
30.         public static string ToJson<T>(T[] array, bool prettyPrint)
31.         {
32.             Wrapper<T> wrapper = new Wrapper<T>();
33.             wrapper.items = array;
34.             return JsonUtility.ToJson(wrapper, prettyPrint);
35.         }
36.  
37.         [Serializable]
38.         private class Wrapper<T>
39.         {
40.             public T[] items;
41.         }
42.     }
43.  

 

Hi all, thank you for sharing the information.
I use JavaScript, but did not find any useful example of how to use JsonUtility.FromJson in JavaScript.
In case anyone is looking for how to deserialize (convert) JSON with array in Unity using JavaScript I've made an example:

Code (JavaScript):

1. // Unity data classses
2. public class Ball { // this is required in both cases: single and array
3.     public var size : float;
4.     public var color : String;
5.     public var weight : int;
6. }
7.  
8. public class Balls { // this is required only in case of array
9.     public var allBalls : Ball[];
10. }
11.  
12. // Get JSON data
13. var ballJson : String = '{"size":1,"color":"red","weight":2}';
14.  
15. // Instantiate data from JSON
16. var oneBall : Ball = JsonUtility.FromJson.<Ball>(ballJson);
17.  
18. // Use the data
19. Debug.Log('RED BALL:\nCOLOR: '+oneBall.color+'\nSIZE: '+oneBall.size+'\nWEIGHT: '+oneBall.weight);
20.  
21. // Get JSON data
22. var ballsJson : String = '{"allBalls":[{"size":"1f","color":"red","weight":2},{"size":"1.2f","color":"blue","weight":3},{"size":0.9,"color":"green","weight":5}]}';
23.  
24. // Instantiate data from JSON with array
25. var manyBalls : Balls = JsonUtility.FromJson.<Balls>(ballsJson);
26.  
27. // Use the data
28. for (var i = 0; i < manyBalls.allBalls.length; i++) {
29.     Debug.Log('#'+i+') BALL:\nCOLOR: '+manyBalls.allBalls[i].color+'\nSIZE: '+manyBalls.allBalls[i].size+'\nWEIGHT: '+manyBalls.allBalls[i].weight);
30. }

You can use JsonUtility.FromJson(ballJson, Ball) instead of JsonUtility.FromJson.<Ball>(ballJson) if you like.

Result looks like:

 

hi @halzate93 thanks for your codes, but your FromJson function seems doesn't work for me. It gives me NullReferenceException.

I have a simple code like below using your FromJson function :

Code (CSharp):

1. void Start () {
2.         TextAsset data = Resources.Load("Creature") as TextAsset;
3.         Debug.Log(data.name);
4.         Debug.Log(data.text);
5.         string dataText = data.ToString();
6.         Creature[] creatures = JsonHelper.FromJson<Creature>(dataText);
7.         Debug.Log(creatures.Length);
8.         for (int i = 0; i < creatures.Length; i++) {
9.             Debug.Log(creatures[i].Name);
10.         }
11.     }

my json file structure is like this :

Code (CSharp):

1. [
2.     {
3.         "Name" : "ARC",
4.         "Level" : "7",
5.         "Stats" : [4,7]
6.     },
7.     {
8.         "Name" : "ARS",
9.         "Level" : "1",
10.         "Stats" : [3,1]
11.     }
12. ]

 

Read Post #15 and Post #33 in this thread. You need to use a wrapper around your json data to make it accessible.

 

Slightly off topic. I've enjoyed reading through this thread, and it's helped me to successfully read and write toJson (using both lists and arrays). I don't suppose anyone here has hit the obstacle of derived classes not serializing correctly? All my data gets serialized as if it was the base type only

 

{
"test1": "first string",
"test2": "second string",
"test3" :
[
{
"title" : "Red ",
"image" : "Image Url"
},
{
"title" : "Green ",
"image" : "Image Url"
},
{
"title" : "Blue ",
"image" : "Image Url"
},
{
"title" : "Yellow ",
"image" : "Image Url"
}
]
}

hi all i am confusing that i need to access the first value of the "buttons" array from this json and then pick up the first value which is "Red" so how can i access this value can you give me some detailing example because i am confused that how to access the array from json in unity i need to debugging the "title" object from the array.

please can you help with some array objects in detaling .

 

Have a look at this:

http://answers.unity3d.com/questions/1123326/jsonutility-array-not-supported.html

 

It is rather frustrating that this is supposedly on the list of thing to fix for like 2 years now. I am finding myself in the same boat here because I need to ingest data coming from a server that I have no control over, and all the data is returned in top level arrays

 

I've recently started using JSON. NET which has overcome alot of the problems I've faced with JSONUtility, so it's definitely worth looking at

 

I've used it in the past. I prefer the speed and simplicity of Unity's built in solution. This is one of the few areas where it falls short.

 

I would agree with you there... it's a sledgehammer. Very capable and flexible, but I always suggest people check out JsonUtility first because if it works for their scenario it will be faster and less allocatey.

 

I know its old, but I am STILL running into the same issue. Is this still not fixed after 2 years?!

 

I don't really think Unity considers it a bug, so they won't be fixing it. It is just a (extremely annoying) limitation of the system since they focused on speed. I don't really buy that considering how easy it is to work around it and still use the same system, but I'm pretty sure that is UT's stance on it

I highly recommend using one of the "wrapper" scripts posted above. They work great.

 

Giving:

He said its "on the list to handle properly in the future". I mean hes still right with "in the future" but...seriously? 2years? I have used his solution in my project now and it works flawless. But seeing that they said "its on the list" and 2years later its...."still on the list?!"

 

It's a big list....https://unity3d.com/unity/roadmap

 

Good point. I did miss that note.

 

@superpig mentioned that they are working on some enhancements, including Dictionary support. Understandably, it's been awhile but keep in mind that this is the serializer that Unity uses internally and JsonUtility exposes that for use. As they add features, this is one area they have to be very careful not to break other things.

 

Didn't work for me.
I do get this error:

ArgumentNullException: Argument cannot be null.
Parameter name: collection
System.Collections.Generic.List`1[System.Object].CheckCollection (IEnumerable`1 collection) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/List.cs:435)
System.Collections.Generic.List`1[System.Object]..ctor (IEnumerable`1 collection) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/List.cs:58)
JsonConvertor.StringToObjectList (System.String jsonStructuredString) (at Assets/JsonConvertor.cs:35)
TestScript.ShowData () (at Assets/TestScript.cs:90)
TestScriptEditor.OnInspectorGUI () (at Assets/Editor/Test/TestScriptEditor.cs:19)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor[] editors, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1253)
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)

Code (CSharp):

1. using System.Collections.Generic;
2. using UnityEngine;
3.  
4. public static class JsonConvertor  {
5.  
6.     public static string ObjectListToString(List<System.Object> listOfObjects)
7.     {
8.         string dataAsString = "[";
9.         dataAsString += System.Environment.NewLine;
10.         for (int i = 0; i < listOfObjects.Count; i++)
11.         {
12.             dataAsString += JsonUtility.ToJson(listOfObjects[i]);
13.  
14.             // Adds a ',' unless it is the last object
15.             if(i < (listOfObjects.Count-1))
16.             {
17.                 dataAsString += ",";
18.             }
19.             dataAsString += System.Environment.NewLine;
20.         }
21.         dataAsString += "]";
22.         return dataAsString;
23.     }
24.  
25.     public static List<System.Object> StringToObjectList(string jsonStructuredString)
26.     {
27.         List<System.Object> dataAsObjectList = new List<System.Object>();
28.  
29.         if (jsonStructuredString != "")
30.         {
31.             Wrapper<System.Object> objectInsideJsonString;
32.             jsonStructuredString = "{ \"items\": " + jsonStructuredString + "}";
33.             objectInsideJsonString = JsonUtility.FromJson<Wrapper<System.Object>>(jsonStructuredString);
34.             dataAsObjectList = new List<System.Object>(objectInsideJsonString.items);
35.         }
36.  
37.         return dataAsObjectList;
38.     }
39.  
40.     [System.Serializable]
41.     private class Wrapper<T>
42.     {
43.         public T[] items;
44.     }
45.  
46. }
47.  
48.