Unity 2D C# - 育儿问题对我的游戏不起作用

Question

So I am trying to make a top-down tycoon game where a truck gives you crates and you sell the crates for money. I have a script for the trucks and it's working just fine except for the first part. So I coded it that when the trucks are spawned 2 crates spawn and are parented to the truck game object, and the issue is that when I run the game, the objects spawn and all, but they aren't parented to the trucks, I have 6 trucks in the scene and only one gets their crate parented. Can someone help?

Code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CarScript : MonoBehaviour
{
   private float speed = 0.01f;

   private Vector3 dropoffLocation;

   private bool hasCrates = true;

   private float dropCratesCooldown = 500f;

   GameObject cratess;

   private float crateUpgrade = 1;

   public GameObject crateUpgrade1;
   public GameObject crateUpgrade2;
   public GameObject crateUpgrade3;
   public GameObject crateUpgrade4;

   private void Start()
   {
      dropoffLocation = new Vector3(3.5f, -7f, 0);

      crateUpgrade1 = GameObject.Find("Boxes In Truck 1");
      crateUpgrade2 = GameObject.Find("Boxes In Truck 2");
      crateUpgrade3 = GameObject.Find("Boxes In Truck 3");
      crateUpgrade4 = GameObject.Find("Boxes In Truck max");

      if (crateUpgrade == 1)
      {
         Instantiate(crateUpgrade1);
         crateUpgrade1.transform.parent = transform;
         //crateUpgrade1.transform.position = new Vector3(0, 0, 0);
      }
   }

   // Update is called once per frame
   void Update()
   {
      if (transform.position.x > 40)
      {
         Destroy(gameObject);
      }

      if (transform.position.x > dropoffLocation.x && hasCrates)
      {
         dropCratesCooldown--;

         if (dropCratesCooldown < 0)
         {
            cratess = transform.GetChild(0).gameObject;

            Destroy(cratess);
            hasCrates = false;
         }
         transform.Translate(0, 0, 0);
      }
      else
      {
         transform.Translate(speed, 0, 0);
      }
   }
}

btw unity doesn't even show me that its an error

Thanks in advance!

Answer 1

Instantiate returns the instantiated game object. That's what you want to assign as a child of the truck. The way you're doing it now, you just keep assigning and reassigning crateUpgrade1 's parent. That's the reason that only one of your trucks get a crate parented to it.

This is how it should be:

GameObject crate = Instantiate(crateUpgrade1);
crate.transform.parent = transform;

One other thing; the standard way to instantiate new objects is to create a prefab asset in the project, then assign a reference to it to CarScript , and then instantiate instances of that prefab. So the crateUpgrade1 = GameObject.Find("Boxes In Truck 1"); part is a little weird.

This is how it's usually done

public class CarScript : MonoBehaviour
{
   // Assign this to your "crate" prefab in the Unity Inspector
   [SerializeField] private GameObject cratePrefab;

   private void Start()
   {
      if (crateUpgrade == 1)
      {
         GameObject crate = Instantiate(this.cratePrefab);
         crate.transform.parent = transform;
      }
   }
}