NullReference.Exveption: Object reference not set to an instance of an object

Questions & Answers
1

The issue appears to be with the Transform “tgt” on line 54: Could someone explain to me what I’m doing wrong?

using UnityEngine;
using System.Collections;

public class TestEnemyScript : MonoBehaviour {
    public GameObject player;
    public float speed;
    private Transform target;
    private float vel;

    FieldOfView fov;
    CharacterController controller;
    Animator animator;

    void Start()
    {
        //store the fov componenet in a variable
        fov = GetComponent<FieldOfView>();
        //store character controller in variable
        controller = GetComponent<CharacterController>();
        //store animator in variable
        animator = GetComponent<Animator>();
    }

    // Update is called once per frame
    void Update ()
    {
        Anim();
        if (fov.visibleTargets != null)
        {
            foreach(Transform t in fov.visibleTargets)
            {
                if (t.gameObject.tag == "Player") { target = t;}
            }
            Move(target);
        }

        if(animator.GetBool("isDying"))
        {
            StartCoroutine(Die());
        }
    }

    IEnumerator Die()
    {  
        yield return new WaitForSeconds(5);
        animator.SetBool("isDying", false);
        Destroy(gameObject);
    }

    void Move(Transform tgt)
    {
        if(animator.GetBool("isDying") == false)
        {
            /*Line 54 */ transform.position = Vector3.MoveTowards(transform.position, new Vector3(tgt.transform.position.x, transform.position.y, tgt.transform.position.z), speed * Time.deltaTime);
            transform.LookAt(new Vector3(tgt.transform.position.x, transform.position.y, tgt.transform.position.z));
        }
       
    }

    void Anim()
    {
        vel = controller.velocity.magnitude;
        Debug.Log(vel);

        //isWalking
        if (vel != 0)
        {
            animator.SetBool("isWalking", true);
        }
        else if (vel == 0)
        {
            animator.SetBool("isWalking", false);
        }
       
    }
}
2

The problem is that when you calls Move(target); (line 34) target will be null if non of visible objects will be called “Player”. Also try to avoid using foreach, instead use for . Foreach creates a new variable for each loop, and afaik if destroys it after the loop is finished, so it will always be null. That’s my suggestion:

if (fov.visibleTargets != null)
{
    for(int i=0; i< fov.visibleTargets.length; i++)
    {
        if (fov.visibleTargets*.gameObject.tag == "Player")*

{
target = fov.visibleTargets*;}*
}
if(target != null)
Move(target);
}