Question by Martinpartin · Aug 15, 2018 at 07:18 PM · c#editor nullreferenceexception serialization

Editor nullreference error when playing second time

I'm building a custom node editor that's serializable so its contents persists on play. When I add some nodes, play, stops play and hit play again I get a NullReferenceError in DrawWindow() here;

              for (int i = 0; i < connections.Count; i++)
              {
                  connections[i].Draw();

It seems the script iterates through the list and and then throws the error at connections[i].Draw(). Below are parts of my editor script and the connections script.

Editor script:

 namespace StoryEditor
 {
     public class StoryEditor : EditorWindow
     {
         #region variables
         public List<SBaseNode> nodes = new List<SBaseNode>();
         public List<Connection> connections = new List<Connection>();
 
         private Vector3 mousePosition;
         [SerializeField]
         private bool clickedOnNode;
         [SerializeField]
         private SBaseNode selectedNode;
 
         [SerializeField]
         private Rect menuBar;
         [SerializeField]
         private float menuBarHeight = 20f;
 
 
         public Connector selectedInPoint;
         public Connector selectedOutPoint;
 
         [SerializeField]
         private bool didPan;
         [SerializeField]
         private Vector2 pan = new Vector2();
 
         [SerializeField]
         private string savePath;
 
         public enum EditorActions
         {
 
             addTriggerNode,
             //add other node types..
             removeNode,
             addConnection,
             removeConnection
         }
 
         #endregion
 
 
 
         #region Init
         [MenuItem("Window/Story Editor")]
         public static void ShowEditor()
         {
             GetWindow<StoryEditor>("StoryEditor");
         }
 
 
         #endregion
 
 
 
         
 
 
         #region GUI Methods
         //window code
         void OnGUI()
         {
             Event e = Event.current;
             mousePosition = e.mousePosition;
             minSize = new Vector2(800, 600);
 
             DrawMenuBar();
             DrawGrid(20, new Color(0.5f, 0.5f, 0.5f, 0.2f));
             DrawGrid(100, new Color(0.5f, 0.5f, 0.5f, 0.4f));
 
             DrawConnectionToMouse(e);
             UserInput(e);
             DrawWindows();
         }
 
 
         //....
    
         void DrawWindows()
         {
             BeginWindows();
             Debug.Log("Connections: " + connections.Count);
             for (int i = 0; i < connections.Count; i++)
             {
                 connections[i].Draw();
                 Debug.Log("Draw iteration " + i + " done");
             }
 
             for (int i = 0; i < nodes.Count; i++)
             {
                 nodes[i].nodeRect = GUI.Window(i, nodes[i].nodeRect, DrawNodes, nodes[i].nodeTitle);
                 nodes[i].DragNode(pan);
 
                 //Note: if node calls drawConnector it has to be within window.
                 nodes[i].inConnector.DrawConnector();
                 nodes[i].outConnector.DrawConnector();
             }
             EndWindows();
 
             if (didPan)
             {
                 Repaint();
                 didPan = false;
             }
 
 
         }

connection script

 using UnityEngine;
 using System.Collections;
 using System;
 using UnityEditor;
 
 namespace StoryEditor
 {
     public class Connection : ScriptableObject
     {
         public Connector inConnector;
         public Connector outConnector;
 
         public Action<Connection> onClickRemoveConnection;
         public Color color = new Color();
         public Color activeColor = new Color(0, 0.7f, 0, 1);
 
         public void Init (Connector inConnector, Connector outConnector, Action<Connection> onClickRemoveConnection)
         {
             this.inConnector = inConnector;
             this.outConnector = outConnector;
             this.onClickRemoveConnection = onClickRemoveConnection;
         }
 
         public void Draw()
         {
             if (outConnector.node.triggered)
             {
                 color = activeColor;
             }
             else
             {
                 color = Color.white;
             }
 
             Handles.DrawBezier( 
                 inConnector.cRect.center,
                 outConnector.cRect.center,
                 inConnector.cRect.center + Vector2.left * 50f,
                 outConnector.cRect.center - Vector2.left * 50f,
                 color,
                 null,
                 2f
                 );
 
             if (Handles.Button((inConnector.cRect.center + outConnector.cRect.center) * 0.5f, Quaternion.identity, 4, 8, Handles.RectangleCap))
             {
                 if (!Application.isPlaying && onClickRemoveConnection != null)
                 {
                     onClickRemoveConnection(this);
                 }
             }
         }
     }
 }

Thanks in advance for any help!

Add comment