属性绘制器

借助属性绘制器，可以通过使用脚本上的特性或通过控制特定 Serializable 类的外观来自定义 __Inspector 窗口__中某些控件的外观。

属性绘制器有两种用途：

• 自定义 Serializable 类的每个实例的 GUI。
• 通过自定义的__属性特性__来自定义脚本成员的 GUI。

自定义 Serializable 类的 GUI

如果有自定义的 Serializable 类，可以使用__属性绘制器__来控制该类在 Inspector 中的外观。请参考以下脚本示例中的 Serializable 类 Ingredient（注意：这些不是编辑器脚本。属性特性类应放在常规脚本文件中）：

JavaScript (example):

enum IngredientUnit { Spoon, Cup, Bowl, Piece }

// Custom serializable class
class Ingredient extends System.Object {
    var name : String;
    var amount : int = 1;
    var unit : IngredientUnit;
}

var potionResult : Ingredient;
var potionIngredients : Ingredient[];

function Update () {
    // Update logic here...
}

C#（示例）：

using UnityEngine;
using System.Collections;

public enum IngredientUnit { Spoon, Cup, Bowl, Piece }

// Custom serializable class
[System.Serializable]
public class Ingredient : System.Object {
    string name;
    int amount = 1;
    IngredientUnit unit;
}

public class Recipe : MonoBehaviour {
    Ingredient potionResult;
    Ingredient[] potionIngredients;

    void Update() {
        // Update logic here...
    }
}

using UnityEngine;
using System.IO;

class Testing : MonoBehaviour{

    enum IngredientUnit { Spoon, Cup, Bowl, Piece }

    // Custom serializable class
    [System.Serializable]
    class Ingredient{
        string name;
        int amount = 1;
        IngredientUnit unit;
    }

    Ingredient potionResult;
    Ingredient[] potionIngredients;

    void Update () {
    // Update logic here...
    }
}

可以使用自定义属性绘制器来更改 Inspector 中 Ingredient 类的每个外观。比较不带有和带有自定义属性绘制器的 Inspector 中 Ingredient 属性的外观：

可以使用 CustomPropertyDrawer 属性将属性绘制器附加到 Serializable 类，然后传入属性绘制器所针对的 Serializable 类的类型。

JavaScript (example):

@CustomPropertyDrawer(Ingredient)
class IngredientDrawer extends PropertyDrawer {
    
    // Draw the property inside the given rect
    function OnGUI (position : Rect, property : SerializedProperty, label : GUIContent) {
        // Using BeginProperty / EndProperty on the parent property means that
        // prefab override logic works on the entire property.
        EditorGUI.BeginProperty (position, label, property);
        
        // Draw label
        position = EditorGUI.PrefixLabel (position, GUIUtility.GetControlID (FocusType.Passive), label);
        
        // Don't make child fields be indented
        var indent = EditorGUI.indentLevel;
        EditorGUI.indentLevel = 0;
        
        // Calculate rects
        var amountRect = new Rect (position.x, position.y, 30, position.height);
        var unitRect = new Rect (position.x+35, position.y, 50, position.height);
        var nameRect = new Rect (position.x+90, position.y, position.width-90, position.height);
        
        // Draw fields - passs GUIContent.none to each so they are drawn without labels
        EditorGUI.PropertyField (amountRect, property.FindPropertyRelative ("amount"), GUIContent.none);
        EditorGUI.PropertyField (unitRect, property.FindPropertyRelative ("unit"), GUIContent.none);
        EditorGUI.PropertyField (nameRect, property.FindPropertyRelative ("name"), GUIContent.none);
        
        // Set indent back to what it was
        EditorGUI.indentLevel = indent;
        
        EditorGUI.EndProperty ();
    }
}

C# (examples):

using UnityEngine;
using UnityEditor;
using System.Collections;

[CustomPropertyDrawer(typeof(Ingredient))]
public class IngredientDrawer : PropertyDrawer {

    // Draw the property inside the given rect
    void OnGUI(Rect position, SerializedProperty property, GUIContent label) {
        // Using BeginProperty / EndProperty on the parent property means that
        // prefab override logic works on the entire property.
        EditorGUI.BeginProperty(position, label, property);

        // Draw label
        position = EditorGUI.PrefixLabel(position, GUIUtility.GetControlID(FocusType.Passive), label);

        // Don't make child fields be indented
        int indent = EditorGUI.indentLevel;
        EditorGUI.indentLevel = 0;

        // Calculate rects
        Rect amountRect = new Rect(position.x, position.y, 30, position.height);
        Rect unitRect = new Rect(position.x+35, position.y, 50, position.height);
        Rect nameRect = new Rect(position.x+90, position.y, position.width-90, position.height);

        // Draw fields - passs GUIContent.none to each so they are drawn without labels
        EditorGUI.PropertyField(amountRect, property.FindPropertyRelative ("amount"), GUIContent.none);
        EditorGUI.PropertyField(unitRect, property.FindPropertyRelative ("unit"), GUIContent.none);
        EditorGUI.PropertyField(nameRect, property.FindPropertyRelative ("name"), GUIContent.none);

        // Set indent back to what it was
        EditorGUI.indentLevel = indent;

        EditorGUI.EndProperty();
    }
}

using UnityEngine;
using UnityEditor;
using System.Collections;


[CustomPropertyDrawer (Ingredient)]
class IngredientDrawer : PropertyDrawer {
    
    // Draw the property inside the given rect
    void OnGUI (Rect position, SerializedProperty property, GUIContent label) {
        // Using BeginProperty / EndProperty on the parent property means that
        // prefab override logic works on the entire property.
        EditorGUI.BeginProperty (position, label, property);
        
        // Draw label
        position = EditorGUI.PrefixLabel (position, GUIUtility.GetControlID (FocusType.Passive), label);
        
        // Don't make child fields be indented
        var indent = EditorGUI.indentLevel;
        EditorGUI.indentLevel = 0;
        
        // Calculate rects
        Rect amountRect = new Rect (position.x, position.y, 30, position.height);
        Rect unitRect = new Rect (position.x+35, position.y, 50, position.height);
        Rect nameRect = new Rect (position.x+90, position.y, position.width-90, position.height);
        
        // Draw fields - passs GUIContent.none to each so they are drawn without labels
        EditorGUI.PropertyField (amountRect, property.FindPropertyRelative ("amount"), GUIContent.none);
        EditorGUI.PropertyField (unitRect, property.FindPropertyRelative ("unit"), GUIContent.none);
        EditorGUI.PropertyField (nameRect, property.FindPropertyRelative ("name"), GUIContent.none);
        
        // Set indent back to what it was
        EditorGUI.indentLevel = indent;
        
        EditorGUI.EndProperty ();
    }
}

使用属性特性来自定义脚本成员的 GUI

属性绘制器__的另一用途是更改脚本中具有自定义__属性特性__的成员的外观。假设要将脚本中的浮点数或整数限制在特定范围内，并在 Inspector__ 中将其显示为滑动条。那么，可以使用内置的 PropertyAttribute__（称为 RangeAttribute__）来执行此操作：

JavaScript (example):

// Show this float in the Inspector as a slider between 0 and 10
@Range (0.0, 10.0)
var myFloat = 0.0;

//C# example.
[Range(0.0f, 10.0f)]
public float myFloat = 0.0f;

C#（示例）：

// Show this float in the Inspector as a slider between 0 and 10
[Range(0.0f, 10.0f)] 
float myFloat = 0.0f;

还可以创建自己的 PropertyAttribute。我们将以 RangeAttribute 的代码为例。该属性必须扩展 PropertyAttribute 类。如果需要，属性可以使用参数并将它们存储为公共成员变量。

JavaScript (example):

class RangeAttribute extends PropertyAttribute {
    var min : float;
    var max : float;
    
    function RangeAttribute (min : float, max : float) {
        this.min = min;
        this.max = max;
    }
}

C# (examples):

using UnityEngine;
using System.Collections;


public class RangeAttribute : PropertyAttribute {
    public float min;
    public float max;

    public RangeAttribute (float min, float max) {
        this.min = min;
        this.max = max;
    }
}

using UnityEngine;
using System.Collections;

public class Testing : PropertyAttribute 
{
        float min;
        float max;
        
        void RangeAttribute (float min, float max) {
            this.min = min;
            this.max = max;
        }
}

拥有该特性之后，就需要创建一个__属性绘制器__来绘制具有该特性的属性。该绘制器必须扩展 PropertyDrawer 类，且必须具有 CustomPropertyDrawer 特性来说明绘制器所针对的特性。

属性绘制器类应放在编辑器脚本中，该脚本位于称为 Editor 的文件夹内。

JavaScript (example):

// Tell the RangeDrawer that it is a drawer for properties with the RangeAttribute.
@CustomPropertyDrawer (RangeAttribute)
class RangeDrawer extends PropertyDrawer {
    
    // Draw the property inside the given rect
    function OnGUI (position : Rect, property : SerializedProperty, label : GUIContent) {
        
        // First get the attribute since it contains the range for the slider
        var range : RangeAttribute = attribute as RangeAttribute;
        
        // Now draw the property as a Slider or an IntSlider based on whether it's a float or integer.
        if (property.propertyType == SerializedPropertyType.Float)
            EditorGUI.Slider (position, property, range.min, range.max, label);
        else if (property.propertyType == SerializedPropertyType.Integer)
            EditorGUI.IntSlider (position, property, range.min, range.max, label);
        else
            EditorGUI.LabelField (position, label.text, "Use Range with float or int.");
    }
}

C# (examples):

using UnityEngine;
using UnityEditor;
using System.Collections;

// Tell the RangeDrawer that it is a drawer for properties with the RangeAttribute.

[CustomPropertyDrawer(typeof(RangeAttribute))]
public class RangeDrawer : PropertyDrawer {

    // Draw the property inside the given rect
    void OnGUI (Rect position, SerializedProperty property, GUIContent label) {

        // First get the attribute since it contains the range for the slider
        RangeAttribute range  = attribute as RangeAttribute;

        // Now draw the property as a Slider or an IntSlider based on whether it's a float or integer.
        if (property.propertyType == SerializedPropertyType.Float)
            EditorGUI.Slider(position, property, range.min, range.max, label);
        else if (property.propertyType == SerializedPropertyType.Integer)
            EditorGUI.IntSlider(position, property, (int) range.min, (int) range.max, label);
        else
            EditorGUI.LabelField(position, label.text, "Use Range with float or int.");
    }
}

请注意，出于性能原因，EditorGUILayout 函数不能用于属性绘制器。