How to Fix NullReferenceException When Rescaling Game Objects in Unity

Learn how to resolve the `NullReferenceException` error in Unity related to rescaling game objects by understanding the underlying issue and applying the correct solution to optimize your 2D game development.
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Understanding and Fixing NullReferenceException in Unity

The Problem: NullReferenceException in ScalePieces Method

You may have written a method ScalePieces() to change the scale of your game pieces, but when you call this method, you receive an error indicating a NullReferenceException. This is a common issue when working with arrays of objects in Unity if those objects are not initialized correctly before trying to access their properties or methods. Here’s a closer look at the error message you may encounter:

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This message indicates that the code is attempting to access a property of an object that hasn’t been instantiated, typically occurring when working with the pieces array.

The Root Cause of the Issue

The core issue lies in the order of operations in your code. Specifically, in the DrawPieces() method, the ScalePieces() method is called inside the loop that populates the pieces array. This can lead to attempts to access elements of the pieces array that have not yet been initialized (set to a GameObject), resulting in the aforementioned error.

Key Cause

Calling ScalePieces too early: By invoking ScalePieces() within the nested loops of DrawPieces(), you might be trying to access entries in the pieces array before they have been filled with instantiated game objects.

The Solution: Correctly Timing the ScalePieces Call

Revised DrawPieces Method

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

By calling ScalePieces() after the nested loops, you ensure that all entries in the pieces array are initialized and valid, allowing you to safely modify their scale without encountering a NullReferenceException.

Conclusion

Understanding the timing of when methods are called and ensuring that all necessary objects are correctly instantiated before usage is crucial in Unity development. By modifying the order of operations in your DrawPieces() method, you can effectively eliminate errors such as NullReferenceException. This technique not only helps streamline your code but also aids in debugging and developing more robust Unity applications.

Now you can continue building your game without the disruptions caused by errors – happy coding!