NullReferenceException error

Unity Engine
1

Hey, while coding I had a problem… the problem was error actually
“NullReffernceException: Object reference not set to an instance of an object TileManager.Start() (at Assets/Scripts/TileManager.cs:16)”
I checked it like 10 times nothing wrong everything is right… I don’t know what have I done wrong in the code :

using UnityEngine;
using System.Collections;

public class TileManager : MonoBehaviour
{
    public GameObject[] tilePrefabs;

    private Transform playerTransform;

    // Use this for initialization
    void Start () {
        playerTransform = GameObject.FindGameObjectWithTag ("Player").transform;
    }
   
    // Update is called once per frame
    void Update () {
   
    }
}

While I’ve created EmptyChild named as TileManager and putted this script on it and in the size of “Tile Prefabs” I’ve putted 5 and clicked enter… 5 empty columns appeared and putted in them 5 prefabs.

What have I done wrong? I don’t find any error I’ve done why this is keep appearing, the code is basically balanced.
if anyone know what should I do… I will appreciate his help!

Thanks,Respectfully.

2

is that your entire script, because it’s throwing the error from line 16 within start… in code you’ve pasted start ends by line 14 and line 16 is a comment…

1 Like
3

Is there a tag on the player? why is the player transform private? just make public and drag the player into it? :open_mouth:

1 Like
4

Never seen a comment throw a null exception before. :smile:

1 Like
5

No I was just trying to re-edit it so many times but didn’t click start so this happens xD

using UnityEngine;
using System.Collections;

public class TileManager : MonoBehaviour
{
    public GameObject[] tilePrefabs;

    private Transform playerTransform;
    private float spawnZ = 0.0f;
    private float tileLength = 10.0f;
    private int amnTilesOnScreen = 7;

    // Use this for initialization
    private void Start () {
        playerTransform = GameObject.FindGameObjectWithTag ("Player").transform;

        for(int i = 0; i < amnTilesOnScreen; i++)
        {
            SpawnTile ();
        }
    }
   
    // Update is called once per frame
    private void Update () {
        if (playerTransform.position.z > (spawnZ - amnTilesOnScreen * tileLength))
        {
            SpawnTile();
        }

    }

    private void SpawnTile(int prefabIndex = -1)
    {
        GameObject go;
        go = Instantiate (tilePrefabs[0]) as GameObject;
        go.transform.SetParent (transform);
        go.transform.position = Vector3.forward * spawnZ;
        spawnZ += tileLength;
    }
}

Now there is 2 errors :
“NullReffernceException: Object reference not set to an instance of an object TileManager.Start() (at Assets/Scripts/TileManager.cs:15)”
“NullReffernceException: Object reference not set to an instance of an object TileManager.Update() (at Assets/Scripts/TileManager.cs:25)”
I don’t know what’s wrong with playerTransform itself :frowning:

I don’t know… I thought making it private make it more readable… My “Player” is untagged, Should I tag it with “Player” or tries public and drag player to it better?
I dunno yet :frowning:

This how luck works :confused:

6

Your “GameObject.FindGameObjectWithTag(“Player”)” function call is failing to find a GameObject with the tag “Player” in your scene.

2 Likes
7

Alright thanks A LOT !!! <3 My player was untagged so I tagged it “Player”

I had another problem I don’t know if I should make another thread or something but let’s ask nothing wont happen :slight_smile:
My ball is flying like 0.5cm from the ground, however when I try to increase the “Y scale” of my ground to don’t let the ball fly when I just start the game it fly again… before I start the game the ball is standing on the ground.
Can you help me out please? sorry for bothering :smile:

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour
{

    private CharacterController controller;
    private Vector3 moveVector;

    private float speed = 7.0f;
    private float verticalVelocity = 0.0f;
    private float gravity = 12.0f;

    void Start()
    {
        controller = GetComponent<CharacterController> ();
    }


    void Update()
    {
        transform.Rotate(6, 0, 0);
        moveVector = Vector3.zero;

        if (controller.isGrounded)
        {
            verticalVelocity = -0.5f;
        }
        else
        {
            verticalVelocity -= gravity * Time.deltaTime;
        }

        // X - Left and Right
        moveVector.x = Input.GetAxisRaw("Horizontal") * speed;


        // Y - Up and Down
        moveVector.y = verticalVelocity;

        // Z - Forward and Backward
        moveVector.z = speed;

        controller.Move(moveVector * Time.deltaTime);
    }
}

Because I want to make it Rigidbody but it doesn’t even touch the ground also I want the ball itself to keep moving forward moveVector.z = speed;
so what should I do :3

8

If you don’t want the ball to move up or down, just change your line of code that says
'moveVector.y = veticalVelocity;"
to
‘moveVector.y = 0.0f;’

That should fix your problem of the ball moving up or down.

9

Nope

10

"If I’m on the ground, move me up (well down, but you’re taking away a negative gravity, so I think it’ll flip the sign) 0.5f units… " if you don’t want it to be 0.5 units off the ground, dont do this :stuck_out_tongue: