NullReferenceException in Ruby's Adventure: 2D Beginner

Unity Engine
1

I try to finish the “Ruby’s Adventure: 2D Beginner”, and when I want to finish “Sprite Animation”, there are some errors. I just copy the code from the tutorial and I tried many times but totally don’t know how to fix it.
The error is:
NullReferenceException: Object reference not set to an instance of an object
Rubycontroller.Update () (at Assets/Script/Rubycontroller.cs:48)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Rubycontroller : MonoBehaviour
{
    public float speed = 3.0f;

    public int maxHealth = 5;
    public float timeInvincible = 2.0f;

    public int health { get { return currentHealth; } }
    int currentHealth;

    bool isInvincible;
    float invincibleTimer;

    Rigidbody2D rigidbody2d;
    Animator animator;
    Vector2 lookDirection = new Vector2(0, -1);

    // Start is called before the first frame update
    void Start()
    {
        rigidbody2d = GetComponent<Rigidbody2D>();

        currentHealth = 4;
    }

    // Update is called once per frame
    void Update()
    {
        float horizontal = Input.GetAxis("Horizontal");
        float vertical = Input.GetAxis("Vertical");

        //Vector2 position = rigidbody2d.position;
        //position.x = position.x + speed * horizontal * Time.deltaTime;
        //position.y = position.y + speed * vertical * Time.deltaTime;

        Vector2 move = new Vector2(horizontal, vertical);

        if (!Mathf.Approximately(move.x, 0.0f) || !Mathf.Approximately(move.y, 0.0f))
        {
            lookDirection.Set(horizontal, vertical);
            lookDirection.Normalize();
        }

        animator.SetFloat("Speed", move.magnitude);
        animator.SetFloat("Look X", lookDirection.x);
        animator.SetFloat("Look Y", lookDirection.y);
       

        Vector2 position = rigidbody2d.position;

        position = position + move * speed * Time.deltaTime;

        rigidbody2d.MovePosition(position);

        if (isInvincible)
        {
            invincibleTimer -= Time.deltaTime;
            if (invincibleTimer < 0)
                isInvincible = false;
        }

    }

    public void ChangeHealth(int amount)
    {
        if (amount < 0)
        {
            animator.SetTrigger("Hit");

            if (isInvincible)
                return;

            isInvincible = true;
            invincibleTimer = timeInvincible;
        }

        currentHealth = Mathf.Clamp(currentHealth + amount, 0, maxHealth);
        Debug.Log(currentHealth + "/" + maxHealth);
    }
}

4675958--440270--upload_2019-6-22_20-55-32.png
4675958--440270--upload_2019-6-22_20-55-32.png3840×2160 909 KB

Appreciate any help!!

2

I can’t see anywhere where do you get a reference to the animator.
You have this line at the top :

Animator animator;

But you never make a reference to it.
You can do it in two ways. Depending if the script is attached to a GameObject that have Animator or not.

You can change the animator declaration to :

public Animator animator;

And then in the editor in the inspector to assign the Animator component.
Or leave it as it is and add in the Start the line :

animator = GetComponent<Animator>();
1 Like
3

Got it, and it works, thank you very very much!

1 Like
4

Thank you!