Add an instantiation of a class to a GameObject ?

Hi guys,

I created a script that generates a number of cars (gameObjects), then for each object of the Cars class add the car, the road it has to go through and the index showing where it arrived.
In the Update method from the script, I have a for that calls a function for the movement of each machine.

I'm sure what I did is not good, even if it works, so I created a script CarManager, but I don't want to read for every car my XML with all path. Can I created a Class (GlobalData) and read there from XML and after that to use it in my CarManager?

I tried something like this, but i get Null exception..

 

GetComponent looks for a component attached to the game object. I am assuming since you will use this GlobalData for all gameobjects that you don't want to attach it to each one?

Try using a Scriptable Object (basically a data container). Change the inheritance of GlobalData from MonoBehaviour to ScriptableObject. Then you could add a reference in the inspector to this scriptable object for each car, or better yet on the car prefab.

Edit: Or make it a class without MonoBehaviour inheritance and you can access is from anywhere using GlobalData.methodname().

 

It is attached to one Game Object.

I tried what you say but doesn't work.

 

You'll need to be more specific. Show what you tried, and explain why/how it didn't work.

 

Error: null

But I think it is not a good idea because if I do ... = new GlobalData() for every car that means I read the XML everytime

 

I'm not sure why you're being evasive with your explanations, but if you are hitting an error please post the error in its entirety and exactly what line the error occurs on. Also don't post pictures of your code, paste the code into the forum using CODE tags.

 

Sorry, I was too tired last night.
I have my class GlobalData which read my XML.

Code (CSharp):

1. public class GlobalData
2. {
3.  
4.     [Tooltip("The resource file that contains the OSM map data")]
5.     public string routesXML;
6.  
7.     [Tooltip("The resource file that contains the OSM map data")]
8.     public string graphXML;
9.  
10.     // Graful cu nodurile rutelor
11.     public List<Node> Graph;
12.  
13.     // Toate rutele generate pentru hartă
14.     public List<Route> Routes;
15.  
16.  
17.     GlobalData()
18.     {
19.         var txtAsset1 = Resources.Load<TextAsset>(routesXML);
20.         var txtAsset2 = Resources.Load<TextAsset>(graphXML);
21.  
22.         XmlDocument doc1 = new XmlDocument();
23.         doc1.LoadXml(txtAsset1.text);
24.         Routes = readAllRoutes(doc1.SelectNodes("allPath/path"));
25.  
26.         XmlDocument doc2 = new XmlDocument();
27.         doc2.LoadXml(txtAsset2.text);
28.         Graph = GetGraph(doc2.SelectNodes("graph/node"));
29.     }
30.  
31.     public List<Node> GetGraph(XmlNodeList nodeList)
32.     {
33.         List<Node> graph = new List<Node>();
34.  
35.         foreach (XmlNode node in nodeList)
36.         {
37.             Node nd = new Node();
38.             nd.ID = System.Convert.ToUInt64(node.Attributes["id"].Value);
39.  
40.             Vector3 point = new Vector3();
41.             point.x = (float)System.Convert.ToDouble((node.Attributes["x"].Value));
42.             point.y = (float)System.Convert.ToDouble((node.Attributes["y"].Value));
43.             point.z = (float)System.Convert.ToDouble((node.Attributes["z"].Value));
44.             nd.Point = point;
45.  
46.             XmlNodeList connection = node.SelectNodes("connection");
47.             foreach (XmlNode c in connection)
48.             {
49.                 Node con = new Node();
50.                 con.ID = System.Convert.ToUInt64(c.Attributes["id"].Value);
51.  
52.                 point.x = (float)System.Convert.ToDouble((c.Attributes["x"].Value));
53.                 point.y = (float)System.Convert.ToDouble((c.Attributes["y"].Value));
54.                 point.z = (float)System.Convert.ToDouble((c.Attributes["z"].Value));
55.                 con.Point = point;
56.  
57.                 nd.Connections.Add(con);
58.             }
59.  
60.             graph.Add(nd);
61.         }
62.         return graph;
63.     }
64.     public List<Route> readAllRoutes(XmlNodeList routesXML)
65.     {
66.         //List<List<Node>> allPath = new List<List<Node>>();
67.         List<Route> routes = new List<Route>();
68.  
69.         foreach (XmlNode p in routesXML)
70.         {
71.             Route route = new Route();
72.             route.OneWay = System.Convert.ToString(p.Attributes["oneway"].Value);
73.             route.StartID = System.Convert.ToUInt64(p.Attributes["startId"].Value);
74.             route.EndID = System.Convert.ToUInt64(p.Attributes["endId"].Value);
75.             route.Nr = System.Convert.ToInt16(p.Attributes["nr"].Value);
76.  
77.             XmlNodeList positions = p.SelectNodes("position");
78.             foreach (XmlNode position in positions)
79.             {
80.                 Node node = new Node();
81.  
82.                 Vector3 point = new Vector3();
83.                 point.x = (float)System.Convert.ToDouble((position.Attributes["x"].Value));
84.                 point.y = (float)System.Convert.ToDouble((position.Attributes["y"].Value));
85.                 point.z = (float)System.Convert.ToDouble((position.Attributes["z"].Value));
86.                 node.Point = point;
87.                 node.ID = System.Convert.ToUInt64(position.Attributes["id"].Value);
88.  
89.                 route.Nodes.Add(node);
90.             }
91.  
92.             routes.Add(route);
93.         }
94.         return routes;
95.     }
96.  
97.     public List<Node> GetGraph()
98.     {
99.         return Graph;
100.     }
101. }
102.  

In CarManager (the script for every car) I use:

Code (CSharp):

1. private void Awake()
2.     {
3.         allData =new GlobalData();
4.  
5.         Graph = allData.GetGraph();
6.     }
7.  

ERROR:

NullReferenceException: Object reference not set to an instance of an object
CarManager.Start

 

SOLVED

Code (CSharp):

1. public class GlobalData: MonoBehaviour
2. {
3.  
4.     [Tooltip("The resource file that contains the OSM map data")]
5.     public string routesXML;
6.  
7.     [Tooltip("The resource file that contains the OSM map data")]
8.     public string graphXML;
9.  
10.     // Graful cu nodurile rutelor
11.     public List<Node> Graph;
12.  
13.     // Toate rutele generate pentru hartă
14.     public List<Route> Routes;
15.  
16.     // xml is ready
17.     public bool dataIsReady = false;
18.  
19.     void Awake()
20.     {
21.         var txtAsset1 = Resources.Load<TextAsset>(routesXML);
22.         var txtAsset2 = Resources.Load<TextAsset>(graphXML);
23.  
24.         XmlDocument doc1 = new XmlDocument();
25.         doc1.LoadXml(txtAsset1.text);
26.         Routes = readAllRoutes(doc1.SelectNodes("allPath/path"));
27.  
28.         XmlDocument doc2 = new XmlDocument();
29.         doc2.LoadXml(txtAsset2.text);
30.         Graph = GetGraph(doc2.SelectNodes("graph/node"));
31.  
32.         dataIsReady = true;
33. .......
34.     }

In script which is attached to car I put:

Code (CSharp):

1.     void Start()
2.     {
3.         GameObject mp = GameObject.Find("Map");
4.         Graph = mp.GetComponent<GlobalData>().Graph;
5.         Routes = mp.GetComponent<GlobalData>().Routes;
6.     ......

The error was generated because I forgod to find the initial GameObject with DataGlobal script.