I'm facing with NullReferenceException Error in Unity2D

I’m trying to find solution to this problem for almost 2 days and I couldn’t find any answers.

Here is my code:

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

public class HealthBar : MonoBehaviour
{
    public float sizeNormalized;
    private Transform bar;
    // Start is called before the first frame update
    private void Start()
    {
        Transform bar = transform.Find("Bar");
    }

    public void SetSize(float sizeNormalized){
        bar.localScale = new Vector3(sizeNormalized,1f);
    }

}

It throws error at line 16, bar.localScale = new Vector3(sizeNormalized,1f);

Please help. Thanks much.

>Solution :

Transform bar = transform.Find("Bar");

Declares and defines a new local variable inside the scope of the method. You want to define your private variable, so you should just write

bar = transform.Find("Bar");

I’m not sure if that’s enough to solve your problem but its a good start.