我如何使一个局部变量在另一个函数可用?

Question

现在我想让我的实例化子弹在与墙碰撞时销毁，但是Visual Studio说'bullet'在OnTriggerEnter2D函数的当前上下文中不存在。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace work.working.worked
{
    public class Shooting : MonoBehaviour
    {
        public static bool firing;
        public Transform firepoint;
        public GameObject bulletprefab;
        public float bulletspeed;
        // Update is called once per frame
        void Update()
        {
            if (firing == false)
            {
                if (Movement.ismoving == false)
                {
                    firing = true;
                    StartCoroutine(Shoot());
                }
            }
        }
        IEnumerator Shoot()
        {
            GameObject bullet = Instantiate(bulletprefab, firepoint.position, firepoint.rotation);
            Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
            rb.AddForce(firepoint.up * bulletspeed, ForceMode2D.Impulse);
            yield return new WaitForSeconds(0.5f);
            firing = false;
        }
        private void OnTriggerEnter2D(Collider2D collision)
        {
            Destroy(bullet);
        }
    }
}

Answer 1

你不能这样做，你不能改变方法签名并将变量作为方法参数传递，因为它是一个统一事件函数，所以它必须保持原样。相反，把它变成一个字段。

using System.Collections.Generic;
using UnityEngine;
namespace work.working.worked
{
    public class Shooting : MonoBehaviour
    {
        public static bool firing;
        public Transform firepoint;
        public GameObject bulletprefab;
        public float bulletspeed;
    private GameObject bullet;
        // Update is called once per frame
        void Update()
        {
            if (firing == false)
            {
                if (Movement.ismoving == false)
                {
                    firing = true;
                    StartCoroutine(Shoot());
                }
            }
        }
        IEnumerator Shoot()
        {
            bullet = Instantiate(bulletprefab, firepoint.position, firepoint.rotation);
            Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
            rb.AddForce(firepoint.up * bulletspeed, ForceMode2D.Impulse);
            yield return new WaitForSeconds(0.5f);
            firing = false;
        }
        private void OnTriggerEnter2D(Collider2D collision)
        {
            Destroy(bullet);
        }
    }
}