c# - 如何在 CustomPropertyDrawer 中设置 SerializedProperty.propertyType

Question

我正在使用这两个库:

• Unity-SerializableDictionary: https://github.com/starikcetin/Unity-SerializableDictionary

• Unity 场景引用: https://github.com/starikcetin/unity-scene-reference

基本上，可序列化字典通过以下检查查看 propertyType 以确定属性是否可以扩展:

static bool CanPropertyBeExpanded(SerializedProperty property)
{
    switch(property.propertyType)
    {
    case SerializedPropertyType.Generic:
    case SerializedPropertyType.Vector4:
    case SerializedPropertyType.Quaternion:
        return true;
    default:
        return false;
    }
}

但是，场景引用似乎已注册为可扩展属性，尽管它不是。这是因为 - 显然 - Unity 将其注册为 Generic 类型。

我可以通过将 SerializedProperty.propertyType 设置为更有意义的类型来简单地解决这个问题，但它是只读的。

那么，如何设置自定义属性抽屉的 SerializedProperty.propertyType？

Answer 1

它没有记录，但类型 Generic 会自动分配给任何自定义类(例如 SceneReference)。您不能更改propertyType，因为它是只读 ...并且您不能告诉编译器将您的自定义类处理为别的……

即使如果您可以……什么是“更有意义的类型”？ SerializedPropertyType 的可用类型是有限的，没有一个对自定义类更有意义。

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这里的主要“问题”是:

SerializableDictionary 抽屉简单地假设通常如果你有一个没有自定义 PropertyDrawer 的自定义(Generic)类 - 所以使用默认抽屉- 它的行为与 Quaternion 或 Vector4 的默认抽屉完全一样:

• 第一行有标签和折页
• 字段/内容在下面绘制，并且仅当属性被折叠时

由于 SceneReference 的抽屉未实现此行为，因此它被绘制在字典的键字段之上。

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所以作为最简单的修复当然你可以简单地删除

case SerializedPropertyType.Generic:

因此 SceneAsset(和所有其他自定义类)被视为正常展开的字段 - 品味问题

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或者，您可以更改 SceneReference 的 PropertyDrawer 以反射(reflect)例如四元数:

• 添加一个 EditorGUI.Foldout 带有改变 property.isExpaned 值的标签
• 将任何内容移到下方一行(可选)
• 将一行添加到属性高度和 if(!property.isExpanded) 的条件

可能看起来像喜欢:

// Made these two const btw
private const float PAD_SIZE = 2f;
private const float FOOTER_HEIGHT = 10f;

public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
    // Move this up
    EditorGUI.BeginProperty(position, GUIContent.none, property);
    {
        // Here we add the foldout using a single line height, the label and change
        // the value of property.isExpanded
        property.isExpanded = EditorGUI.Foldout(new Rect(position.x, position.y, position.width, lineHeight), property.isExpanded, label);

        // Now you want to draw the content only if you unfold this property
        if (property.isExpanded)
        {
            // Optional: Indent the content
            //EditorGUI.indentLevel++;
            //{

            // reduce the height by one line and move the content one line below
            position.height -= lineHeight;
            position.y += lineHeight;

            var sceneAssetProperty = GetSceneAssetProperty(property);

            // Draw the Box Background
            position.height -= FOOTER_HEIGHT;
            GUI.Box(EditorGUI.IndentedRect(position), GUIContent.none, EditorStyles.helpBox);
            position = boxPadding.Remove(position);
            position.height = lineHeight;

            // Draw the main Object field
            label.tooltip = "The actual Scene Asset reference.\nOn serialize this is also stored as the asset's path.";


            var sceneControlID = GUIUtility.GetControlID(FocusType.Passive);
            EditorGUI.BeginChangeCheck();
            {
                // removed the label here since we already have it in the foldout before
                sceneAssetProperty.objectReferenceValue = EditorGUI.ObjectField(position, sceneAssetProperty.objectReferenceValue, typeof(SceneAsset), false);
            }
            var buildScene = BuildUtils.GetBuildScene(sceneAssetProperty.objectReferenceValue);
            if (EditorGUI.EndChangeCheck())
            {
                // If no valid scene asset was selected, reset the stored path accordingly
                if (buildScene.scene == null) GetScenePathProperty(property).stringValue = string.Empty;
            }

            position.y += paddedLine;

            if (!buildScene.assetGUID.Empty())
            {
                // Draw the Build Settings Info of the selected Scene
                DrawSceneInfoGUI(position, buildScene, sceneControlID + 1);
            }

            // Optional: If enabled before reset the indentlevel
            //}
            //EditorGUI.indentLevel--;
        }
    }
    EditorGUI.EndProperty();
}

public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
{
    var sceneAssetProperty = GetSceneAssetProperty(property);
    // Add an additional line and check if property.isExpanded
    var lines = property.isExpanded ? sceneAssetProperty.objectReferenceValue != null ? 3 : 2 : 1;
    // If this oneliner is confusing you - it does the same as
    //var line = 3; // Fully expanded and with info
    //if(sceneAssetProperty.objectReferenceValue == null) line = 2;
    //if(!property.isExpanded) line = 1;

    return boxPadding.vertical + lineHeight * lines + PAD_SIZE * (lines - 1) + FOOTER_HEIGHT;
}

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现在看起来像

[Serializable]
public class TestDict : SerializableDictionary<string, SceneReference> { }

public class Example : MonoBehaviour
{
    public SceneReference NormalReference;

    public TestDict DictExample = new TestDict();
}

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