如何在关卡中只收集一次金币

Question

I have some levels in my game. Some of the levels contain a gold coin. I need the player to be able to collect it only once. If the user plays the same level again the coin should not appear again. (I'm using unity and c#)

Here the Script attached to the coin:

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

public class Goldcoin : MonoBehaviour
{
    void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Player"))
         {
           SaveManager.Instance.state.goldcoin++;
           SaveManager.Instance.Save();
           Destroy(gameObject);
         }
    }
}

Answer 1

What you want is data persistance between scenes.

Data persistence means that even if you close the app, or change the scene, this data will persist, won't be deleted.

If you want persistance only in the same program execution, you can have an object that won't be destroyed on every Scene load, using DontDestroyOnLoad .

But if you want to keep this information between multiple executions of the app you need something else, like a file. You can store the state of the current scene (or even the whole game) in a multiple ways, the easyiest one is:

1. Create a Serializable class that will keep the information of the scene/level.
2. Serialize that class into a file (like a JSON ) when you want to save changes.
3. Deserialize that file when you restart the game, to convert the information on the file to your virtual class, again.

If you are not familiar with JSON's, you can check my JsonManager Repo.