NullReferenceException

Unity Engine
1

I keep getting the error “NullReferenceException : Object reference not set to an instance of an object Health.Update () ( at Assets/Scripts/Health.cs:21)”

Here is my code:

using UnityEngine;
using System.Collections;

public class Health : MonoBehaviour {

    float lastPosistionY = 0f;
    float fallDistance = 0f;
    float currentHealth = 20f;

    Transform player;

    private CharacterController controller;

    // Use this for initialization
    void Start () {
        controller = GameObject.Find("FirstPersonCharacter").GetComponent<CharacterController>();
    }
   
    // Update is called once per frame
    void Update () {   
        if(lastPosistionY > player.transform.position.y)
        {
            fallDistance += lastPosistionY - player.transform.position.y;
        }

        lastPosistionY = player.transform.position.y;

        if(fallDistance >= 5 && controller.isGrounded)
        {
            currentHealth -= 5;
            ApplyNormal();
        }

        if(fallDistance <= 5 && controller.isGrounded)
        {
            ApplyNormal();
        }
    }

    void ApplyNormal() {
        fallDistance = 0;
        lastPosistionY = 0;
    }
}
2

So none help to get? I still haven’t figured out this error

3

Apparantly, playet is null, which makes sense because you never assign it

4

Then how can i assign the player? This script worked perfectly fine in the JS version

5

You need to initialize the player variable. You can do it in the Start method:
player = this.gameObject.transform;,
or you can make it public and then, in the editor, drag and drop your player object inside the player variable field (inside the inspector.)

6

Alternativally, if you want it to stay private you can give it the [SerializeField] attribute:

[SerializeField]
private Transform player;

You will still be able to assign it in the inspector despite the fact that the field isnt public

7

I am new to unity so i don’t know what to switch “this” with.

Thank you, i completely forgot that command exists