NullReferenceException, but it HAS a reference

Trying to write a code for object to reference an image and change it's sprite, but it says that it has a null exception. Image and sprite are linked and GetComponent is present as well. What is causing the problem?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5.  
6. public class testhook : MonoBehaviour
7. {
8.     public Image fesh;
9.     public Sprite tfish;
10.     // Start is called before the first frame update
11.     void Start()
12.     {
13.         fesh = GetComponent<Image>();
14.         Debug.Log("start");
15.     }
16.  
17.     // Update is called once per frame
18.     void Update()
19.     {
20.  
21.         if (Input.GetKey(KeyCode.Space))
22.         {
23.             // This is where error happens
24.             fesh.sprite = tfish;
25.         }
26.     }
27. }
28.  

 

If you're getting a null error, then it's null. Simple as that.
Either fesh is null because your GetComponent<Image>() call isn't on the same object that has the Image Component or your sprite is null.

 

That's the thing, image is referenced to an image object, and sprite isn't null
Here's screenshots https://imgur.com/a/1S3Sx1g

 

Problem solved, turns out GetComponent image was unnecessary and furthermore somehow conflicting with sprite change.

 

Your problem was as stated before from Brath, your gameObject which used "GetComponent" didnt had a "Image" Component which lead to make your "fesh" variable "null"