Object reference not set to an instance of an object (Scripts calling objects which only exist in certain scenes)

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Right, I feel like despite the title of this question, it's a bit more in depth.

Basically I have a pause menu which references various objects in the scene. It contains buttons which allow the player to change colour, and abilities given to that colour. So I have it set up that each button references a "colour change" script onClick which has different methods to set each colour mode (red mode(), blueMode() etc).

This colour change script also references the script which controls the pause menu. So when you select a colour, it calls the pause menu script and the "Resume()" method.

My problem is that I seem to need to attach all of the references manually to each object in the scene containing the scripts through the editor. As using a "GameObject.find.." will flash up an "object reference not set to..." in scenes not containing those objects (main menu, level select menu).

I feel like it would be easier if I could just reference the other scripts to call these functions, rather than the objects in the scenes which the scripts are attached to?

No doubt I'm doing something completely stupid but right now I have no clue! Also apologies if this has been answered before, I didn't know what to search!

Also for the colour change buttons, the pause menu will be in every level. Currently I have to assign each button the reference to the colour change script and select the method for onClick in the editor. They are all prefabs and yet when I click apply, this setting doesn't persist between scenes?

Here's my colour change script.

  public Color32 playerColour;
     public SpriteRenderer[] sprites;
     public pauseMenu pauseM;
     public bool blueBool = false;
     public bool redBool = false;
     public bool greenBool = false;
     public bool yellowBool = false;
 
     // Use this for initialization
     void Start () {
         normalMode();
     }
     
     // Update is called once per frame
     void Update () {
         for (int i = 0; i < sprites.Length; i++)
         {
             sprites[i].color = playerColour;
         }
     }
 
     public void normalMode()
     {
         playerColour = new Color32(191, 191, 191, 255);
         pauseM.Resume();
         blueBool = false;
         redBool = false;
         greenBool = false;
         yellowBool = false;
     }
     public void blueMode(){
         if (!blueBool)
         {
             playerColour = Color.blue;
             pauseM.Resume();
             blueBool = true;
         }
         else
         {
             normalMode();
         }
     }
     public void redMode()
     {
         if (!redBool)
         {
             playerColour = Color.red;
             pauseM.Resume();
             redBool = true;
         }
         else
         {
             normalMode();
         }
     }
     public void greenMode()
     {
         if (!greenBool)
         {
             playerColour = Color.green;
             pauseM.Resume();
             greenBool = true;
         }
         else
         {
             normalMode();        
         }
     }
     public void yellowMode()
     {
         if (!yellowBool)
         {
             playerColour = Color.yellow;
             pauseM.Resume();
             yellowBool = true;
         }
         else
         {
             normalMode();
         }
     }

Answer 1

Best Answer

Answer by unidad2pete · Aug 21, 2017 at 03:50 PM

If the script with the function you need is named "ScriptWhitFunctions" for example, you can find all those scripts in the scene:

 public ScriptWhitFunctions[] scriptsToFound;
     
     void Start()
     {
         scriptsToFound = FindObjectsOfType<ScriptWhitFunctions>();
         foreach (ScriptWhitFunctions script in scriptsToFound)
         {
             script.FunctionToCall();
         }
     }

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fergie77 · Aug 21, 2017 at 04:00 PM 0

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Hi, I'm not quite sure what you mean. I'm not really looking for scripts. The problem I have is that the scripts reference each other but have to be assigned in the editor. This link is lost between scenes?

unidad2pete fergie77 · Aug 21, 2017 at 04:24 PM 0

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From what I understand, you have a button that when you click it, changes something in the scripts you have previously assigned in the editor, but when changing the scene, those scripts may not exist in the current scene and when you click, you receive null exception, It is right?

With this code, assigned to the OnClick of the button, searches for all the objects that contain the component that you want to access and you can change its properties or call its functions, if there are none in the scene nothing happens, because in each click on button, searchs for objects that currently exist.

Object reference not set to an instance of an object (Scripts calling objects which only exist in certain scenes)

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