How to Properly Use a SerializeReference Field in Unity

Discover how to effectively implement the `SerializeReference` attribute for interfaces in Unity, solving common serialization issues and enhancing your game development workflow.
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Understanding SerializeReference in Unity

When developing in Unity, you may find the need to manage a list of components that share the same interface. This is especially true if you're designing a feature where multiple scripts need to respond to the same event, such as collision detection. One way to achieve this in Unity is by using the SerializeReference attribute. However, many developers face challenges, especially regarding how to effectively use it with interfaces. Let's explore the problem and develop a solution together.

The Problem

Imagine you are tasked with creating a class that holds a list of scripts. These scripts all implement the same interface, allowing them to respond to events such as collisions. For example, you may have an interface called ICollisionScript, which requires implementing classes like RandomEffect to define how they interact with a BallController object.

However, when you attempt to add instances of your implementing classes to a list of the interface type using the SerializeReference attribute, you encounter a setback: you can't drag and drop these scripts into the Unity inspector. Why is that?

The Solution

The limitation arises from the fact that Unity does not serialize interfaces by default in the inspector. Here's how you can overcome this issue:

1. Derive from Unity Object Classes

To help Unity recognize your implementing classes for serialization, you can derive your scripts from a class that Unity supports, such as MonoBehaviour or ScriptableObject. In most cases, using MonoBehaviour is more suitable if you need functionalities such as attaching scripts to GameObjects or handling lifecycle events.

Example Modifications:

[[See Video to Reveal this Text or Code Snippet]]

2. Use the Odin Inspector

If you're looking for a more advanced option, the Odin Inspector is a popular asset that allows for interface serialization in the inspector. While it provides the functionality you might seek, be cautious, as it can introduce additional complexities, particularly related to code stripping and maintenance.

Important Considerations

Hassle vs. Simplicity: While Odin Inspector can enhance your development experience, it's essential to consider whether the additional complexity it brings is worth it for your project.

Future-proofing: Choosing to derive from Unity's supported types may provide a more straightforward path for your project going forward, ensuring compatibility with Unity's evolving features.

Conclusion

Using a SerializeReference to manage lists of interface implementations in Unity can seem daunting at first. Yet, with the right strategies—deriving from Unity's object classes or considering reliable third-party tools like Odin Inspector—you can effectively build and manage your game components. Remember, understanding how Unity handles serialization will empower you to create more dynamic and flexible game mechanics with confidence.

Now go ahead, adapt these approaches, and take your Unity projects to the next level!