如何检查 Unity Inspector 空参数和不正确值的脚本

Question

我正在努力使我的 Unity 游戏代码尽可能健壮，理想情况下，我希望能够在游戏启动之前抛出异常，例如在编译时，如果 Unity Inspector 参数丢失或不正确（例如 null 或超出范围）。

目前我在Awake() 上使用Attributes 和UnityEngine.Assertions 的组合来检查空引用或不正确的值；在游戏启动时抛出异常（而不是在执行期间的意外点），例如：

public class PlayerMovement : MonoBehaviour
{
    [SerializeField]
    [Tooltip("Rigidbody of the Player.")]
    private Rigidbody playerRigidBody;

    [SerializeField]
    [Tooltip("Forward force of the Player.")]
    [Range(100f, 50000f)]
    private float forwardForce = 6000f;

    [SerializeField]
    [Tooltip("Sideways force of the Player.")]
    [Range(10f, 1000f)]
    private float sidewaysForce = 120f;

    private GameManager gameManager;

    void Awake()
    {
        // Cache essential references
        gameManager = GameObject.FindGameObjectWithTag("GameManager").GetComponent<GameManager>();

        // Assert that all required references are present and correct
        UnityEngine.Assertions.Assert.IsNotNull(gameManager, "Member \"gameManager\" is required.");
        UnityEngine.Assertions.Assert.IsNotNull(playerRigidBody, "Member \"Rigidbody\" is required.");
        //UnityEngine.Assertions.Assert.IsTrue(ForwardForce > 100, "\"ForwardForce\" must be greater than 100");
        //UnityEngine.Assertions.Assert.IsTrue(SidewaysForce > 10, "\"SidewaysForce\" must be greater than 10");
    }

    ...
}

这是最佳做法，还是有更好的方法在游戏启动前验证基本参数？

Answer 1

不是真的在编译时，但如果您想在每次在 Unity 中打开项目、重新编译代码或加载新场景时都进行检查，您可以使用 [InitializeOnLoad] 和 SceneManager.sceneLoaded。

首先有例如像

这样的界面

public interface INullReferenceChecker
{
    void CheckReferences();
}

然后有一个全局编辑器脚本，例如Assets/Editor/RunNullChecks.cs（重要的是是放在Editor所以后来被剥离了）

[InitializeOnLoad]
public class RunNullChecks
{
    public static RunNullChecks
    {
        // first of all also add a callback so it gets re-run everytime you switch a scene

        // removing it first makes sure it is only added once
        EditorSceneManager.sceneOpened -= Run;
        EditorSceneManager.sceneOpened += Run;

        Run();
    }

    private static void Run(Scene scene, LoadSceneMode mode)
    {
        Run();
    }

    public static void Run()
    {
        // here it depends a bit on your needs
        // you either can check only stuff in the Scene like
        var nullCheckers = FindObjectsOfType<INullReferenceChecker>();
        // this gets only active and enabled components!
        // or you could include all prefabs, ScriptableObjects using
        //var nullCheckers = Resources.FindObjectsOfTypeAll<INullReferenceChecker>();

        // and then let them do whatever they implemented
        foreach(var tester in nullCheckers)
        {
            tester.CheckReferences();
        }
    }
}

那么你就会有

public class PlayerMovement : MonoBehaviour, INullReferenceChecker
{
    ...

    public override void CheckReferences()
    {
        UnityEngine.Assertions.Assert.IsNotNull(gameManager, "Member \"gameManager\" is required.");
        UnityEngine.Assertions.Assert.IsNotNull(playerRigidBody, "Member \"Rigidbody\" is required.");


        // you could also simply go for
        if(!gameManager) Debug.LogErrorFormat(this, "Member \"{0}\" is required.", nameof(gameManager));
        if(!playerRigidBody) Debug.LogErrorFormat(this, "Member \"{0}\" is required.", nameof(playerRigidBody));
    }
}

---

另一种选择也可能是使用[ExecuteInEditMode] 属性。

这使得

• 每次打开项目/加载场景/向场景添加新组件时都会调用Awake 方法
• Update 每次更改场景中的内容时都会调用该方法

然后您可能会禁用某些代码块，例如在Update 中检查Application.IsPlaying 和/或Application.isEditor。