Decoding JSON to an Object

Hi,
I would be happy for tips how to manage and deserialize a mixed JSON file (which has string, other JSONs, arrays and more).

I'm trying to decode the following JSON file, using 'JSONobject' plugin.
https://api.myjson.com/bins/zazd

It was loaded just fine (i'm loading the whole text to text-object).
I also had created a class and inner classes that will match the JSON structure, and I managed the code to create on runtime the amount of main objects the json has (for example, it has a list of 3 types of donuts, so the code create an array of 3 'donuts' objects, and I can see it from the inspector).
Also I could easily printed to the log all keys and value, which are mixed types.

The problem began when i'm trying to load the inner data (as ID or name of one of those inner JSON objects) into the class that had been created.
I get the error: "NullReferenceException: Object reference not set to an instance of an object".
Any ideas?


/////////////////////////////////////////////////////////
/// Decoder - Working progress... ///
///////////////////////////////////////////////////////

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using UnityEngine.UI;
4.  
5. public class Json_Decoder_Work: MonoBehaviour {
6.  
7.     public string url_json = "https://api.myjson.com/bins/zazd";
8.     public GameObject TextViewer;
9.  
10.     // Internal variables
11.     private bool isInternalBatters;
12.     private bool isInternalTopping;
13.     private bool isExternal;
14.     private bool isID;
15.     private bool isType;
16.     private bool isName;
17.     private bool isPPU;
18.  
19.     // Temporary variables
20.     private int tempObjectIndex;
21.     private DounutObject tempObject;
22.     private int tempID;
23.     private string tempType;
24.     private string tempName;
25.     private float tempPPU;
26.  
27.     // Load & Present the JSON String text
28.     IEnumerator Start() {
29.  
30.         // Get the JSON text from web
31.         WWW wwwOBJ = new WWW(url_json);
32.         yield return wwwOBJ;
33.  
34.         // Load the JSON text into string
35.         TextViewer.GetComponent<Text>().text = wwwOBJ.text;
36.  
37.         // DeSerialize the json string into object
38.         JSONObject j = new JSONObject(wwwOBJ.text);
39.         accessData(j);                                  
40.     }
41.  
42.  
43.     //access data (and print it) - CHANGED
44.     void accessData(JSONObject obj)
45.     {
46.         switch(obj.type)
47.         {
48.         case JSONObject.Type.OBJECT:
49.             for(int i = 0; i < obj.list.Count; i++)
50.             {
51.                 string key = (string)obj.keys[i];
52.  
53.                 switch (key) {
54.                 case "data":
55.                     isExternal = true;
56.                     break;
57.                 case "batter":
58.                     isInternalBatters = true;
59.                     break;
60.                 case "topping":
61.                     isInternalTopping = true;
62.                     break;
63.                 case "id":
64.                     Debug.Log("updating ID :) :) :)");
65.                     if (!isInternalBatters && !isInternalTopping)
66.                     {
67.                         isID = true;
68.                         Debug.Log("ID -> ON!");
69.                     }
70.                     break;
71.  
72.                 default:
73.                     break;
74.                 }
75.  
76.                 JSONObject j = (JSONObject)obj.list[i];
77.                 Debug.Log(" I=" + i + "->");
78.                 Debug.Log(key);
79.                 accessData(j);
80.                 Debug.Log("<-");
81.             }
82.             break;
83.  
84.         case JSONObject.Type.ARRAY:
85.             if (isExternal){
86.                 ObjectsManager.controller.food = new DounutObject[obj.list.Count];
87.                 Debug.Log("JSON contains object x" + obj.list.Count);
88.                 isExternal = false;
89.  
90.                 tempObjectIndex = 0;
91.  
92.                 for (int i = 0 ; i<obj.list.Count; i++)
93.                 {
94.                     JSONObject j = obj.list[i];
95.                     accessData(j);
96.                     tempObjectIndex++;
97.                 }
98.             }
99.             if (isInternalTopping){
100. //                toppings[] tempTop = new toppings[obj.list.Count];
101. //                ObjectsManager.controller.food[0].setTopping(obj.list.Count);
102.                 Debug.Log("Topping has" + obj.list.Count + " layers");
103.                 isInternalBatters = false;
104.             }
105.             if (isInternalBatters){
106. //                ObjectsManager.controller.food[tempObjectIndex].setBatter(obj.list.Count);
107.                 Debug.Log("Batters has" + obj.list.Count + " layers");
108.                 isInternalBatters = false;
109.             }
110.  
111.             break;
112.  
113.  
114.  
115.         case JSONObject.Type.STRING:
116.             Debug.Log(obj.str);
117.             if (isID && !isInternalBatters && !isInternalTopping){
118.                 ObjectsManager.controller.food[tempObjectIndex].id = obj.str;
119.                 isID = false;
120.                 Debug.Log("ID -> OFF");
121.             }
122.             break;
123.  
124.         case JSONObject.Type.NUMBER:
125.             Debug.Log(obj.n);
126.             break;
127.  
128.         case JSONObject.Type.BOOL:
129.             Debug.Log(obj.b);
130.             break;
131.  
132.         case JSONObject.Type.NULL:
133.             Debug.Log("NULL");
134.             break;  
135.         }
136.     }
137. }

// Object Manager

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class ObjectsManager : MonoBehaviour {
5.  
6.     public static ObjectsManager controller;
7.     public DounutObject[] food;
8.  
9.     void Awake(){
10.         controller = this;
11.     }
12.  
13.     public void updateID (int position , string id) {
14.         food[position].setID(id);
15.     }
16.  }

// Object class

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [System.Serializable]
5. public class DounutObject {
6.     public string id;
7.     public string type;
8.     public string name;
9.     public float ppu;
10.     public batters[] batter;
11.     public toppings[] topping;
12.  
13.  
14.     // Set topping
15.     public void setTopping (int amount) {
16.         this.topping = new toppings[amount];
17.     }
18.  
19.     // Set Batter
20.     public void setBatter (int amount) {
21.         this.batter = new batters[amount];
22.     }
23.  
24.     public void setID (string idX)
25.     {
26.         this.id = idX;
27.     }
28. }
29.  
30. [System.Serializable]
31. public class batters {
32.     public int id;
33.     public string type;
34. };
35.  
36. [System.Serializable]
37. public class toppings {
38.     public int id;
39.     public string type;
40. }
41.  

 

What line of code is actually throwing the exception?