Скачать или смотреть Resolving the GetComponent Dilemma in Unity: Why Equals Returns False

Discover how Unity's `GetComponent` method can lead to unexpected behavior with comparisons. Learn step-by-step to solve the `Equals` issue in your game development process.
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Resolving the GetComponent Dilemma in Unity: Why Equals Returns False

When developing games in Unity, developers often encounter perplexing issues, especially when dealing with object references. One such issue arises when using the GetComponent method and finding that the Equals method returns false unexpectedly. This post explores this problem through the lens of a specific scenario involving a ProtagonistActor class and its interaction with an InputManager class.

The Problem: Unexpected Results from Equals

Consider the following scenario: you have a class ProtagonistActor which contains a state object of type ActorState. In another class, InputManager, you're trying to compare the state of the ProtagonistActor with a cached instance of ActorState. Instead of getting the expected result, your logs are showing that both Equals and == return false.

Here's the relevant snippet:

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Upon execution, the output is something perplexing:

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This is concerning because logically, you might expect both values to be the same. So why is this happening?

Understanding the Core Issue

To grasp the root of the problem, we need to break down how object comparison works in C# .

When you compare objects in C# , .Equals checks for value equality (assuming it's overridden properly) while == checks for reference equality unless otherwise specified. In this case, we aren't seeing the expected true values because:

GetComponent<ProtagonistActor>() assigns the reference of _protagonistActor but creates a new instance of _actorState in Awake().

As a result, when you modify _actorState in the InputManager, you're working with a cached reference that doesn't match the newly instantiated instance in ProtagonistActor.

Step-by-Step Breakdown of Events:

Awake Method Order:
The Awake method in InputManager is called before Awake in ProtagonistActor.

Value Caching:
In InputManager, _actorState captures the reference to _protagonistActor._actorState before it is overwritten with the new ActorState instance.

New Instance Creation:
In ProtagonistActor, the InitiateActorState method creates a brand-new instance of ActorState, leading to two separate objects with different states.

Debugging the Flow

To diagnose the flow of your methods, inserting debug logs can be beneficial. For instance, log messages at the start of the Awake methods can clarify the order of operations:

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The Solution

To resolve the issue, we need to ensure that the sequence of method calls is correct and that we're always working with the same object instance. Here are a couple of approaches:

Change Execution Order:
Use the ExecuteInEditMode attribute or set the script execution order to ensure that ProtagonistActor initializes before InputManager.

Retain the Same ActorState Reference:
In your input handling class, retrieve the actor state only after it’s been initialized:

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

By implementing these changes, your comparisons should return true, as the same instance of ActorState will be referenced, allowing proper value comparison.

Conclusion

Understanding how object references and method execution order impact your comparisons in Unity is essential for effective game development. By ensuring that your object instances remain consistent and properly initializing your classes in the correct order, you can avoid the frustration of unexpected false comparisons.

By following these practices, you will improve the reliability of your code and maintain cleaner logic in your game. Happy coding!