Unity - 在检查器中自定义绘制结构

Question

我有一个自定义结构，代码如下：

[Serializable]
public struct HexPoint : IEquatable<HexPoint>
{
    public readonly int x;
    public readonly int y;
    public readonly int z;
    
    // Some custom methods for initializations and operators
}

如果我将 x、y 和 z 变量设为非只读，它们就会在统一检查器中正常显示。但是，我有一些他们需要满足的规则（实际上是 x+y+z=0），所以我添加了 readonly 以防止人们弄乱它。

但是作为只读变量，它们不会显示（因为它们不能被修改）！:(

我想知道它们是否是我在统一检查器中显示它们的一种方式，类似于 PropertyDrawer。我知道我可以将我的结构切换到一个类，因为 PropertyDrawer 是为类保留的，但我想将它保留为一个结构。

那么，有没有办法显示值？并最终使用自定义初始值设定项修改它们？

非常感谢！

Answer 1

readonly使它们也non-serialized-> 不显示在检查器中

注意这PropertyDrawer是不局限于class类型，但也可以使用struct的类型。

实际上不需要一个CustomPropertyDrawer.

您可以拥有公共只读属性来访问私有字段并在 Inspector 使用中显示它们，[SerializeField]这使得它们只能通过 Inspector 而不能通过其他类进行编辑。

[Serializable]
public struct HexPoint : IEquatable<HexPoint>
{
    // Those are not displayed in the inspector, 
    // readonly and accessible by other classes
    public int x { get { return _x; } }
    public int y { get { return _y; } }
    public int z { get { return _z; } }

    // if you prefer you can also use the expression body style instead
    //public int x => _x;
    //public int y => _y;
    //public int z => _z;

    // Those are displayed and editable in the Inspector
    // but private and therefor not changeable by other classes
    [SerializeField] private int _x;
    [SerializeField] private int _y;
    [SerializeField] private int _z;

    public bool Equals(HexPoint other)
    {
        return _x == other._x && _y == other._y && _z == other._z;
    }

    public override bool Equals(object obj)
    {
        return obj is HexPoint other && Equals(other);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            var hashCode = _x;
            hashCode = (hashCode * 397) ^ _y;
            hashCode = (hashCode * 397) ^ _z;
            return hashCode;
        }
    }
}

如果您真的想使用PropertyDrawer另外还不允许在检查器中编辑这些值但仍然保存并查看它们，您可以添加一个，例如

[Serializable]
public struct HexPoint : IEquatable<HexPoint>
{
    // Those are not displayed in the inspector, 
    // readonly and accessible by other classes
    public int x { get { return _x; } }
    public int y { get { return _y; } }
    public int z { get { return _z; } }

    // if you prefer you can also use the expression body style instead
    //public int x => _x;
    //public int y => _y;
    //public int z => _z;

    // Those are displayed and editable in the Inspector
    // but private and therefor not changeable by other classes
    [SerializeField] private int _x;
    [SerializeField] private int _y;
    [SerializeField] private int _z;

    public bool Equals(HexPoint other)
    {
        return _x == other._x && _y == other._y && _z == other._z;
    }

    public override bool Equals(object obj)
    {
        return obj is HexPoint other && Equals(other);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            var hashCode = _x;
            hashCode = (hashCode * 397) ^ _y;
            hashCode = (hashCode * 397) ^ _z;
            return hashCode;
        }
    }

#if UNITY_EDITOR

    [CustomPropertyDrawer(typeof(HexPoint))]
    public class HexPointDrawer : PropertyDrawer
    {
        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
        {
                return EditorGUIUtility.singleLineHeight * (EditorGUIUtility.wideMode ? 1 : 2);
        }

        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            // Find the SerializedProperties by name
            var x = property.FindPropertyRelative(nameof(_x));
            var y = property.FindPropertyRelative(nameof(_y));
            var z = property.FindPropertyRelative(nameof(_z));

            // Using BeginProperty / EndProperty on the parent property means that
            // prefab override logic works on the entire property.
            EditorGUI.BeginProperty(position, label, property);
            {
                // Makes the fields disabled / grayed out
                EditorGUI.BeginDisabledGroup(true);
                {
                    // In your case the best option would be a Vector3Field which handles the correct drawing
                    EditorGUI.Vector3IntField(position, label, new Vector3Int(x.intValue, y.intValue, z.intValue));
                }
                EditorGUI.EndDisabledGroup();
            }
            EditorGUI.EndProperty();
        }
    }

#endif
}

更改后检查值的提示MonoBehaviour.OnValidate可能对您感兴趣