Cannot assign assets to variables via inspector: NullReferenceException

[Ralp]

Below is what I am trying to do, play a sound and an animation by pressing fire button (previously assigned on input manager). Please note I use C# language:

using UnityEngine;
using System.Collections;

public class ShotgunFire : MonoBehaviour {
	
	public AnimationClip ShotClip;
	public AudioClip ShotSound;
	Animation anim;
	AudioSource audio;
	
	// Use this for initialization
	void Start () 
	{
		anim.AddClip(ShotClip, "fire");
	}
	
	// Update is called once per frame
	void Update () 
	{
		if(Input.GetButton("Fire") == true)
		{
			audio.PlayOneShot(ShotSound);
			anim.Play("fire");
		}
		
	}
}

The script above was attached as a component to my shotgun model, as shown on the picture below. As you may see, I have assigned assets to all public variables on the script, as requested.

And when I press play it keeps giving a NullReferenceException error, which is making me fry my brains trying to solve it! Lights please?

[prototype7]

as Benproductions1 said for instance

void Start () {
        anim = this.gameObject.AddComponent<Animation>();
        anim.AddClip(ShotClip, "fire");
	}

[EliteMossy]

you can either put these in Start()

        gameObject.AddComponent<Animation>();
        gameObject.AddComponent<AudioSource>();

then you should be able to

audio.PlayOneShot(ShotSound);
animation.Play("fire");

but in all honesty, this is how i would do it

using UnityEngine;
using System.Collections;
 
[RequireComponent(typeof(AudioSource))]
[RequireComponent(typeof(Animation))]
public class ShotgunFire : MonoBehaviour {
 
    public AnimationClip ShotClip;
    public AudioClip ShotSound;
 
    // Use this for initialization
    void Start () 
    {
       animation.AddClip(ShotClip, "fire");
    }
 
    // Update is called once per frame
    void Update () 
    {
       if(Input.GetButton("Fire") == true)
       {
         audio.PlayOneShot(ShotSound);
         animation.Play("fire");
       }
 
    }
}

Good luck

[Ralp]

EliteMossy, you forgot to say I had to add the components directly into the object, not associate them to variables in my script. But thanks for your help!

So this is how I solved the problem:

• Instead of associating the components to variables in script, I added them directly into the object, making the inspector look like this:

• Then, by using RequireComponent attributes and unity engine’s property variables (in this case audio and animation), I was able to control the object’s components by its class. The final code is as follows:

   using UnityEngine;
   using System.Collections;
   
   [RequireComponent(typeof(AudioSource))]
   [RequireComponent(typeof(Animation))]
   public class ShotgunFire : MonoBehaviour {
   		
       // Use this for initialization
       void Start (){}
    
       // Update is called once per frame
       void Update () 
       {
          if(Input.GetButton("Fire") == true)
          {
          	audio.Play();
   		animation.Play();
          }
    
       }
   }
  

I am migrating from XNA, where I had to do everything by code. So trust me when I say unity is being a challenging transition (but hopefully worth).