Unity检视面板的继承方法研究

对于检视面板 Inspector 的面板继承方式对项目来说是很有必要的, 比如一个基类, 写了一个很好看的检视面板[CustomEditor(typeof(XXX))],

可是所有子类的面板无法直接继承这个CustomEditor, 有些人的解决方案是把子类写检视面板的代码独立出来, 然后子类面板直接去调用这些Layout,

非常浪费人力物力.

　　最近发现有个 DecoratorEditor 脚本, 它实现了对 Unity 自带检视面板的扩展, 看到它实现某个类型的面板Inspector的方法, 就是使用Editor.CreateEditor 这个API

创建了一个相应的Editor, 然后调用它的OnInspectorGUI() 方法来绘制原有面板的, 于是可以从这个地方着手.

 　　从设计上来说 [CustomEditor(typeof(XXX))] 在耦合上并没有太多的耦合, Unity 开发组的想法应该就是一个Editor对应一个组件, 它们对应类型之间的继承关系不应该

互相影响, 保证泛用性和独立性. 

　　原始的Editor脚本和类型是这样的:

基类 :

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public class TestBaseClass : MonoBehaviour {     public float abc; } // 检视面板 [CustomEditor(typeof(TestBaseClass))] public class TestBaseClassInspector : Editor {     TestBaseClass _target;     private void OnEnable()     {         _target = target as TestBaseClass;     }     public override void OnInspectorGUI()     {         _target.abc = EditorGUILayout.FloatField("基类变量 : ", _target.abc);     } }

子类1 :

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public class TestCamera : TestBaseClass {     public Camera cam; } // 检视面板 [CustomEditor(typeof(TestCamera))] public class TestCameraInspector : Editor {     TestCamera _target = null;     private void OnEnable()     {         _target = target as TestCamera;     }     public override void OnInspectorGUI()     {         base.OnInspectorGUI();                   _target.cam = EditorGUILayout.ObjectField("一次继承变量 : ", _target.cam, typeof(Camera), true) as Camera;     } }

子类2 : 

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public class TestUntiy : TestCamera {     public int hahah; } // 检视面板 [CustomEditor(typeof(TestUntiy))] public class TestUntiyInspector : Editor {     TestUntiy _target = null;     private void OnEnable()     {         _target = target as TestUntiy;     }     public override void OnInspectorGUI()     {         base.OnInspectorGUI();         _target.hahah = EditorGUILayout.IntField("二次继承变量 : ", _target.hahah);     } }

　　

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1	TestBaseClass

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1	TestCamera : TestBaseClass

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1	TestUntiy : TestCamera<br><br>非常简单的继承关系, TestUnity的检视面板如下, 没有继承关系

 

　　那么在继承的设计上, 也应该遵循Unity的设计原则, 在继承类型 : Editor 以及 base.OnInspectorGUI(); 绘制基类方法上做文章.

如果使用简单的继承比如:

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[CustomEditor(typeof(TestCamera))] public class TestCameraInspector : TestBaseClassInspector {     TestCamera _target = null;     private void OnEnable()     {         _target = target as TestCamera;     }     public override void OnInspectorGUI()     {         base.OnInspectorGUI();         _target.cam = EditorGUILayout.ObjectField("一次继承变量 : ", _target.cam, typeof(Camera), true) as Camera;     } }

　　会出现很多问题, 如基类的OnEnable方法没有被触发, 基类面板报错等, 所有生命周期都要写虚方法, 每个重写方法都要注意, 很麻烦.

　　而Editor.CreateEditor创建的Editor是有生命周期的. 创建一个中间类型 InspectorDecoratorEditor, 大家都继承它就可以了, 而绘制基类对象的方法就改为

DrawBaseInspectorGUI<T>(), 这样就能方便地自己定义需要绘制的基类了.

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public class InspectorDecoratorEditor : Editor {     public static readonly System.Type EndType = typeof(UnityEngine.MonoBehaviour);     // end type dont need show in inspector     public static readonly System.Type BaseEditorType = typeof(UnityEditor.Editor);     // CustomEditor must inherit from it, filter     public static readonly BindingFlags CustomEditorFieldFlags = BindingFlags.NonPublic | BindingFlags.Instance;    // flag     // type cache[Assembly, [scriptType, customEditorType]]     protected static Dictionary<Assembly, Dictionary<System.Type, System.Type>> ms_editorReferenceScript         = new Dictionary<Assembly, Dictionary<System.Type, System.Type>>();     protected List<Editor> m_inheritEditors = null;     // cached editors     // ctor, use ctor instead Mono life circle, more user friendly     public InspectorDecoratorEditor()     {         CacheEditorReferenceScript();     }     #region Main Funcs     /// <summary>     /// Cache all CustomEditor in current Assembly     /// </summary>     protected void CacheEditorReferenceScript()     {         var editorAssembly = Assembly.GetAssembly(this.GetType());      // editor may in diferent assemblies         if(ms_editorReferenceScript.ContainsKey(editorAssembly) == false)         {             Dictionary<System.Type, System.Type> cachedData = new Dictionary<System.Type, System.Type>();             var types = editorAssembly.GetExportedTypes();             foreach(var editorType in types)             {                 if(editorType.IsSubclassOf(BaseEditorType))                 {                     var scriptType = GetTypeFormCustomEditor(editorType);                     if(scriptType != null)                     {                         cachedData[scriptType] = editorType;                     }                 }             }             ms_editorReferenceScript[editorAssembly] = cachedData;         }     }     /// <summary>     /// Draw a Target Type Inspector, call OnInspectorGUI     /// </summary>     /// <typeparam name="T"></typeparam>     protected virtual void DrawBaseInspectorGUI<T>() where T : InspectorDecoratorEditor     {         if(m_inheritEditors == null)         {             m_inheritEditors = new List<Editor>();             Dictionary<System.Type, System.Type> scriptEditorCache = null;             if(ms_editorReferenceScript.TryGetValue(Assembly.GetAssembly(this.GetType()), out scriptEditorCache) && scriptEditorCache != null)             {                 var baseType = target.GetType().BaseType;                 while(baseType != null && baseType != EndType)                 {                     System.Type editorType = null;                     if(scriptEditorCache.TryGetValue(baseType, out editorType) && editorType != null)                     {                         m_inheritEditors.Add(Editor.CreateEditor(targets, editorType));                     }                     baseType = baseType.BaseType;                 }             }         }         if(m_inheritEditors.Count > 0)         {             for(int i = m_inheritEditors.Count - 1; i >= 0; i--)             {                 var drawTarget = m_inheritEditors[i];                 if(drawTarget && drawTarget.GetType() == typeof(T))                 {                     drawTarget.OnInspectorGUI();   // draw target type only, avoid endless loop                     break;                 }             }         }     }     #endregion     #region Help Funcs     public static System.Type GetTypeFormCustomEditor(System.Type editorType)     {         var attributes = editorType.GetCustomAttributes(typeof(CustomEditor), false) as CustomEditor[];         if(attributes != null && attributes.Length > 0)         {             var attribute = attributes[0];             var type = attribute.GetType().GetField("m_InspectedType", CustomEditorFieldFlags).GetValue(attribute) as System.Type;             return type;         }         return null;     }     #endregion }

　　

　　

　　修改后的Editor代码如下, 修改的只有继承类以及DrawBaseInspectorGUI<T>函数, 注意这里对于T来说是没有类型检查的, 可是在函数中是有类型匹配的,

就算传入错误类型也是安全的 :

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[CustomEditor(typeof(TestBaseClass))] public class TestBaseClassInspector : InspectorDecoratorEditor {     TestBaseClass _target;     private void OnEnable()     {         _target = target as TestBaseClass;     }     public override void OnInspectorGUI()     {         _target.abc = EditorGUILayout.FloatField("基类变量 : ", _target.abc);     } } [CustomEditor(typeof(TestCamera))] public class TestCameraInspector : InspectorDecoratorEditor {     TestCamera _target = null;     private void OnEnable()     {         _target = target as TestCamera;     }     public override void OnInspectorGUI()     {         DrawBaseInspectorGUI<TestBaseClassInspector>();         _target.cam = EditorGUILayout.ObjectField("一次继承变量 : ", _target.cam, typeof(Camera), true) as Camera;     } } [CustomEditor(typeof(TestUntiy))] public class TestUntiyInspector : InspectorDecoratorEditor {     TestUntiy _target = null;     private void OnEnable()     {         _target = target as TestUntiy;     }     public override void OnInspectorGUI()     {         DrawBaseInspectorGUI<TestCameraInspector>();         _target.hahah = EditorGUILayout.IntField("二次继承变量 : ", _target.hahah);     } }

　　然后看看检视面板现在的样子, 完美绘制了基类面板:

DrawBaseInspectorGUI<T>() 这个绘制基类的请求强大的地方就是可以选择从哪个类型开始绘制, 比如
DrawBaseInspectorGUI<TestCameraInspector>();
换成
DrawBaseInspectorGUI<TestBaseClassInspector>();
那么 TestCameraInspector 这个检视面板就被跳过去了 :

 

　　虽然有很多方式能够绘制或者继承子类检视面板, 不过这个应该是个泛用度很高的方案. Over.