如何使用 C# 在 Unity2D 中制作杀戮计数器？

Question

I want to make a kill counter but for some reason it's not working. Here is what i did I create a new empty GameObject Game Manager And add a new component Score , Here is the code:

using UnityEngine;
using UnityEngine.UI;

public class Score : MonoBehaviour
{
    public Text kills_UI;
    private int Kills_Counts; //How many kills
    
    public void Increase_score() //This will update the UI text to the current kills count 
    {
        Kills_Counts++;
        kills_UI.text = Kills_Counts.ToString();
    }
}

After that i called this function in the enemy script BulletColision after he is killed:

using UnityEngine;

public class BulletColision : MonoBehaviour
{
    Score kills_score;

    void Start()
    {
        kills_score = GetComponent<Score>();
    }

    public void OnCollisionEnter2D(Collision2D others) //When a bullet collide with en enemy prefab 
    {
        if (others.gameObject.CompareTag("Enemy"))
        {
            Destroy(gameObject); //Destroy the enemy
            kills_score.Increase_score(); //Calling the function from 'GameManager'
            Destroy(others.gameObject); //Destroy the bullet
            
        }
            
    }
}

Answer 1

The problem is with your kills_score reference, if you do:

kills_score = GetComponent<Score>();

You are searching for Score component on your BulletCollision , which I guess do not have Score component since it's a bullet.

Quick fix:

Attach to your GameManager a new TAG like "GameManager", then use

kills_score = GameObject.FindWithTag("GameManager").GetComponent<Score>();

instead of

kills_score = GetComponent<Score>();

To quickly validate this make your score variable public and see in your editor if the reference is correctly set.

Also and as a side note, try to maintain your variables with lowerCamelCame nomenclature, meaning that starts with lower case.