Question Missing an "object reference" for another script's variable

I've been working on a script that functions as a pick-up system for a player to unlock new abilities. In this case, the ability is to double jump. My problem is within trying to increase the variable I use to adjust how many jumps the player can use: doubleJumpCountMax.

I can include the script working with this one if needed, but this is the one I'm working on that currently holds the problem:

Code (CSharp):

1. public class ItemPickup : MonoBehaviour
2. {
3.     //Used for checking if specifically *player* picking up/colliding with item
4.     [SerializeField] private LayerMask playerColliding;
5.  
6.     public GameObject Player; //Assigned in the Unity UI (Drag n' dropped the player object into this field)
7.     private CircleCollider2D circleColl;
8.  
9.     //Used to reference PlayerMovement script, which holds the double jump mechanic
10.     PlayerMovement playerMovementScript;
11.  
12.     void Start()
13.     {
14.         //Assigns circleColl with the collider of the current item object
15.         circleColl = GetComponent<CircleCollider2D>();
16.     }
17.  
18.     // !PROBLEM! Supposed to increase the max amount of jumps the player has to "unlock" the double jump ability
19.     void FixedUpdate()
20.     {
21.         if (IsGrabbed())
22.             PlayerMovement.doubleJumpCountMax = 1;
23.             //"doubleJumpCountMax" is a variable from the PlayerMovement script to limit how many jumps the player can use
24.     }
25.  
26.     //Checks to see if the player has picked up the item with a boxcast showing if it has collided with the player
27.    //(which involves the CircleCollider2D's bounds as the origin and size of the boxcast)
28.     private bool IsGrabbed()
29.     {
30.         return Physics2D.BoxCast(circleColl.bounds.center, circleColl.bounds.size, 0f, Vector2.left, .5f, playerColliding);
31.     }
32. }

Now I'm just met with the error message of:
error CS0120: An object reference is required for the non-static field, method, or property 'PlayerMovement.doubleJumpCountMax' even though I wouldn't expect there to be an object required for the variable that is already defined as just an int

I tried to leave notes to help explain the process a bit more, hope it helps!

I appreciate any feedback!

 

Get rid of:

Code (CSharp):

1. public GameObject Player; //Assigned in the Unity UI (Drag n' dropped the player object into this field)
2.  

instead, make this one public:

Code (CSharp):

1. //Used to reference PlayerMovement script, which holds the double jump mechanic
2. public PlayerMovement playerMovementScript;

Now do your drag and drop thing in the editor for that field instead. And then to use it:

Code (CSharp):

1. void FixedUpdate()
2. {
3.     if (IsGrabbed())
4.         playerMovementScript.doubleJumpCountMax = 1;
5.         //"doubleJumpCountMax" is a variable from the PlayerMovement script to limit how many jumps the player can use
6. }

There's rarely a good reason to reference the GameObject itself unless you want to just call SetActive() on it. Otherwise it's simpler to reference a component directly.

 

Got it, I hadn't considered grabbing the script directly for some reason. Thank you!

 

It's still possible when you grab the GameObject - you'd just have to call GetComponent on it to get your actual script instance. Your main problem was:

Code (CSharp):

1. PlayerMovement.doubleJumpCountMax = 1;

Because you're trying to use the class name "PlayerMovement" instead of an actual variable of type PlayerMovement. You need a specific instance of the class to do things with, otherwise the code doesn't know which PlayerMovement you mean.