Problem with the tutorial Code ?

I was following this tutorial
http://www.thegamecontriver.com/2014/09/create-level-lock-unlock-system-unity-46.html
every thing is fine except one error that pop up from no where

Code (CSharp):

1. [/B]
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class LevelSelectScript : MonoBehaviour {
6.  
7. private int worldIndex;
8. private int levelIndex;
9.  
10. void  Start (){
11. //loop thorugh all the worlds
12. for(int i = 1; i <= LockLevel.worlds; i++){
13. if(Application.loadedLevelName == "World"+i){
14. worldIndex = i;
15. CheckLockedLevels();
16. }
17. }
18. }
19.  
20. //Level to load on button click. Will be used for Level button click event
21. public void Selectlevel(string worldLevel){
22. Application.LoadLevel("Level"+worldLevel); //load the level
23. }
24.  
25. //uncomment the below code if you have a main menu scene to navigate to it on clicking escape when in World1 scene
26. /*public void  Update (){
27. if (Input.GetKeyDown(KeyCode.Escape) ){
28. Application.LoadLevel("MainMenu");
29. }
30. }*/
31. //function to check for the levels locked
32. void  CheckLockedLevels (){
33. //loop through the levels of a particular world
34. for(int j = 1; j < LockLevel.levels; j++){
35. levelIndex = (j+1);
36. if((PlayerPrefs.GetInt("level"+worldIndex.ToString() +":" +levelIndex.ToString()))==1){
37. GameObject.Find("LockedLevel"+(j+1)).active = false;
38. Debug.Log ("Unlocked");
39. }
40. }
41. }
42. }
43. [B]

So, How to fix it ?

 

I think the error occours, cause the script can't find then "LockedLevel" with the right number.
First, you have to look for the number he can't find. Try a "Debug.Log(j.ToString())" before line 8.

 

Code (csharp):

1. GameObject.Find("LockedLevel"+(j+1)).active = false;

Didn't find anything. Debug what this does.

With all these string dependencies you're bound to run into this sort of error.

 

Just looking at that code, I suspect that tutorial was written by someone in their second week of using Unity.... so many bad newbie habits, encouraged and enshrined in a tutorial. It's also out of date. .active is now deprecated, and .SetActive(false) should be used instead.

But yes, Okto247 is correct. There should be a GameObject in your scene named LockedLevel1 (or some other number), and there isn't. It's possible the name was slightly mistyped in your scene or something along those lines.

....one of a million reasons GameObject.Find should never be used... I can walk through how to create a much better system than the one this tutorial is recommending if you'd like.

 

That's a weird way to code level selection. Suggest abandoning the tutorial and doing a different one.