NullReferenceException in my class

Questions & Answers
1

I am working on this code that will enable me to move the camera forward or back based on a button press handled by another class. Here is the code that handles the camera to move:

using UnityEngine;
using System.Collections;

public class NavigationalCamera : MonoBehaviour {
    public float moveSpeed;
    
    void Update()
    {
        NavigateForward();
    }
    [HideInInspector]
    public void NavigateForward()
    {
        transform.Translate(Vector3.forward * moveSpeed * Time.deltaTime);
        if (Camera.main.transform.position.z >= 60)
        {
            moveSpeed = 0.0f;
        }
    }
}

This is the class I am using to call it:

using UnityEngine;
using System.Collections;

/// 
/// This class handles the user's background info
/// 
[ExecuteInEditMode]
public class myTestClass: MonoBehaviour {

NavigationalCamera obj_navCamera;

//Used for storing the size and position of the backdrop window
public Rect GUIRectWindow;
public Rect btn_Continue;
/// <summary>
/// Initializes all variables
/// </summary>
void Awake()
{
    obj_navCamera   = GameObject.FindGameObjectWithTag("MainCamera").GetComponent<NavigationalCamera>();
}
public void OnGUI()
{
    myMainWindow();
}
/// <summary>
/// Displays the background survey that the user will fill out
/// </summary>
public void myMainWindow()
{
    // Make a backgroound box and center it
    GUI.Box(GUIRectWindow, "Press the Button");

    //set up an action when the user clicks on the button
    if (drawButon(btn_Continue, "Continue"))
    {
        obj_navCamera.NavigateForward();
    }
}
/// <summary>
/// Draws a button
/// </summary>
/// <param name="rect"></param>
/// <param name="buttonName"></param>
/// <returns></returns>
bool drawButon(Rect rect, string buttonName)
{

    if (GUI.Button(new Rect(GUIRectWindow.x + rect.x, GUIRectWindow.y + rect.y, rect.width, rect.height), buttonName))
    {
        return true;
    }
    return false;
}

}

When I run this in the game and press the button it throws me a null reference exception and for the life of me I just can’t get it to work. Can anyone help me figure out what to do in order to fix it? Thank you in advance!

2

Im guessing the error is caused by your obj_navCamera , see if you can drag your main camera into the Inspector IF there is an option for it.

Also another thing which might cause issues is :

if (Camera.main.transform.position.z >= 60)

Im pretty sure that position related values are float values and not Integers, so you might want to change it to 60f