NULL Image problem

So, following along with a tutorial about building a grid-based scroll box (like for an RPG inventory) and I am at a total loss about why a simple call to change an Image.sprite turned in to a nightmare of silliness...or maybe I've been staring at it too long and I can't see the solution...

Now the videos are nearly one and a half years old, but I've made other types of UI scroll boxes from these tutorials with no issue at all. Only the Image object seems to be the problem. So I came here and found quite a few NULL Image posts but none quite matched this problem. Most had to do with GetComponent which I use in the function that calls this one and it works fine there - yet this function fails with flying colors...

Anyway any tips I could get here would help. A lot. Very frustrating stuff.

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.UI;
6.  
7. public class SchedulerGridButton : MonoBehaviour
8. {
9.  
10.     [SerializeField]
11.     private SchedulerGridControl SchedulerGrid;
12.  
13.     // The culprit...
14.     public Image iconImg;
15.  
16.     public void SetImage(Sprite myImage)
17.     {
18.         // This function is called from another class to set the sprite to change the
19.         // UI button image. The image is sent and received as it should be but
20.         // iconImg is always NULL.
21.  
22.         // This proves to me myImage is there because it shows the name of the
23.         // myImage Sprite name every time I run it.
24.         Debug.Log("MyImage.name = " + myImage.name);
25.  
26.         /// ...and here is the problem.
27.         // the sprite that is supposed to be set here cannot because iconImg is
28.         // always NULL.
29.         if (iconImg != null)
30.         { iconImg.sprite = myImage; }
31.         else { Debug.Log("** iconImg == null"); }
32.     }
33.  
34. }
35.  

 

You need to assign an image to iconImg. You can either do that in the inspector or from another script.

If you think you have already done that type t:SchedulerGridButton in the hierarchy search box to check that you don't have an instance of the class on a gameobject you didn't know about.