Serialize objects while keeping references to asset

Hello World.

(first, sorry if my english is not perfect)

I'm trying to do a tricky serializing stuff, here is a little description of what i want to do :
- I have got a Scriptable Object, it contains a list of other objects.
- These object types all implement an abstract class.
- In some of those implementation, i need to reference some assets.

I know it could not be really understandable so I made a UML inspired diagram :


But i don't manage to properly serialize my list of objects. I tried three ways for now :
- By making my abstract class inherits of Scriptable Object : I've got "Type mismatch" in my inspector in the scriptable object list
- By making my abstract class inherits of UnityEngine.Object : I've got "None" in my inspector in the scriptable object list
- By using JsonUtility.Serialize/Deserialize : Everything works except that the reference to the assets are not saved when i restart Unity

Thanks a lot for your future help

 

Type mismatch is because it can't serialize it.
I had the same issue as well, I ended up using the Odin plugin.

https://forum.unity.com/threads/solved-saving-scriptableobject-into-json.521193/

 

Honestly I can not say that I fully understand what you are trying to achieve, but there was recently a post on Unity blog that might be relevant: https://blogs.unity3d.com/2018/07/19/spotlight-team-best-practices-guid-based-references/

 

It's a Scriptable Object containing a list with polymorphed objects. Meaning a list of abstract class type objects, which will be filled with objects that implement the base abstract class type. Just like his UML diagram suggests.

Something like this, Health Potion is by Core an Item but the serialization system tries to serialize it as an Item not a Health Potion. This causes it to be a type mismatch.

Code (CSharp):

1. public class Inventory : ScriptableObject
2. {
3.     public List<Item> Items;
4. }
5.  
6. [Serializable]
7. public abstract class Item
8. {
9.     public int ID;
10. }
11.  
12. [Serializable]
13. public class Consumable : Item
14. {
15.  
16. }
17.  
18. [Serializable]
19. public class HealthPotion : Consumable
20. {
21.     public int HealAmount = 9001;
22. }

Unity cannot serialize polymorphed objects... it will just show up as Type Missmatch when you add things at runtime.

I was working on an inventory that contained a list of Items. Both were scriptable objects, but Items are polymorphed objects. Because an Item could be a Consumable, Equipment or Quest item or whatever. It's an implementation of the base class. But Unity doesn't see it as an Item but as the implemented class, causing a type mismatch.