ActionScript 3中的类反射

什么是反射
反射 (Reflection) 是指在程序在运行时 (run-time) 获取类信息的方式. 诸如实现动态创建类实例, 方法等. 在很语言中都有相关的的实现, 如 Java 和 c# 等

反射有什么用
在 as3 与 as2 不同, 类实例中任何元素, 如变量 (variable), 访问器 (accessor, 即 getter / setter), 方法 (method) 都是不可被 for..in 遍历的 (不是默认哦, 目前我还没找到办法可以让他被遍历),
并且不管你是否继承自 Object (默认继承就是 Object, 不写也一样), 是否把类声明为 dynamic.
或许有人会问自然是 Object 的子类, 不是可以用 setPropertyIsEnumerable 来设置是否隐藏变量么.
很遗憾的是经过的我的尝试, 在类里使用 setPropertyIsEnumerable("属性名") 编译器报告方法可能未定义.
随后尝试 super.setPropertyIsEnumerable("属性名"), 编译通过但抛运行时错误, 同样是方法未定义 -_-
而其他方法诸如 propertyIsEnumerable("属性名") 却可以正常使用

新建一个 ActionScript 项目, 分别创建下面 2 个类:

Dummy.as

package
{
    public dynamic class Dummy extends Object
    {
        public var variable1:String;
        public function Dummy () {
            variable1 = "我是字符串";

            // 使用下面 2 个句子分别会报告编译时错误和运行时错误
            // setPropertyIsEnumerable("variable1");
            // super.setPropertyIsEnumerable("accessorOfVar1");
        }

        public function get accessorOfVar1 ():String {
            return "通过访问器访问, variable1 : " + variable1;
        }

    }
}

ReflectionSample.as

package {
    import flash.display.Sprite;

    public class ReflectionSample extends Sprite
    {
        public function ReflectionSample () {
            testPropsEnumeration();
        }
        /**
         * 测试 for..in 遍历
         *
         */
        private function testPropsEnumeration ():void {
            trace("测试 for..in 循环, 遍历 Dummy 的实例");
            var dummy:Dummy = new Dummy();

            for (var i:String in dummy)
                trace( i + " : " + dummy[i] );
        }
    }
}

最后测试 ReflectionSample, 记得用 debug 模式. 控制台中只会出现:

QUOTE:
------------------------------------------------------------
测试 for..in 循环, 遍历 Dummy 的实例
------------------------------------------------------------

显然 dummy 中的元素都没有被遍历出.

在 as1, 2 中很简单就可以实现的问题在 as3 得换个办法了, 谁让他们是传统的脚本语言呢.而在 as3 中, 就得通过反射来解决这个问题了. 方法会在文后介绍

动态创建实例

* 这部分内容帮助中已经有例子, 我摘要一些翻译一下, 不过我的 e 文很烂. 希望大家能看得懂.

as3 使用 flash.util.getDefinitionByName 动态获取类 (Class) 引用
帮助中该方法的描述 :

QUOTE:
------------------------------------------------------------
public function getDefinitionByName(name:String):Object
返回参数 name 中指定的类引用

参数 name:String - 类名称
返回 Object - 返回参数 name 中指定的类引用
错误 ReferenceError - 找不到参数 name 对应的公共定义
------------------------------------------------------------

使用方法如下:

获取类 flash.text.TextField 的引用. as 语句是无异常的类型转换. 如果转换失败那么目标变量将被设置成 null

var ClassReference:Class = getDefinitionByName("flash.text.TextField") as Class;

实例化所引用的类, 并设置一些属性

var instance:TextField = new ClassReference() as TextField;
instance.autoSize = "left";
instance.text = "我通过 getDefinitionByName 动态创建";

最后添加到场景中并显示

addChild(instance);

修改后的 ReflectionSample.as:

package {

import flash.display.Sprite;

import flash.utils.getDefinitionByName;

import flash.text.TextField;

public class ReflectionSample extends Sprite

{

public function ReflectionSample () {

getDefinitionByNameSample();

}

/**

* 使用 flash.utils.getDefinitionByName 动态获取类 (Class) 并创建实例

private function getDefinitionByNameSample ():void {

var ClassReference:Class = getDefinitionByName("flash.text.TextField") as Class;

var instance:TextField = new ClassReference() as TextField;

instance.autoSize = "left";

instance.text = "我通过 getDefinitionByName 动态创建";

addChild(instance);

}

动态获取类名称, 超类 (Superclass) 名称
有点像之前版本中的 typeof, 这个方法返回的是字符串

QUOTE:
------------------------------------------------------------
public function getQualifiedClassName(value:*):String
返回类的完全限定名 (fully qualified class name, qualified 我不知道怎么翻了..)

参数 value:* - 想要得到完全限定名的对象. 他可以是任何 ActionScript 类型, 对象实例, 简单类型如 uint 以及类类型.
返回 String - 包含类的完全限定名的字符串
------------------------------------------------------------

QUOTE:
------------------------------------------------------------
public function getQualifiedSuperclassName(value:*):String
返回目标对象基类的完全限定名,
本函数提供比 describeType 更简便的方法来获取基类的名称
提示: 本函数限制只寻找实例的继承层次，而 describeType() 函数使用的是类对象继承.
调用 describeType() 函数时返回的是基于超类以的类继承结构. 而 getQualifiedSuperclassName() 将忽略类的继承结构直接返回最接近的继承对象
例如, 理论上 String 类继承自 Class, 但调用 getQualifiedSuperclassName(String) 时返回的是 Object. 换句话说, 不管你传递的是类还是类的实例, 他们的返回值都是一样的

参数 value:* - 任何值.
返回 String - 基类的完全限定名, 如果没有的话返回 null
------------------------------------------------------------

例子:

实例化新的 Sprite, 然后获取他的类名并输出

var sprite1:Sprite = new Sprite();
var classNameOfSprite:String = getQualifiedClassName(Sprite);
trace("Sprite 的类名 : " + classNameOfSprite); // Sprite 的类名 : flash.display::Sprite

超类

var superclassNameOfSprite:String = getQualifiedSuperclassName(Sprite);
trace("Sprite 的超类 (基类) 类名 : " + superclassNameOfSprite); // Sprite 的超类 (基类) 类名 : flash.display::DisplayObjectContainer

根据刚刚获取的类名使用创建实例

var SpriteClass:Class = getDefinitionByName(classNameOfSprite) as Class;
var sprite2:Sprite = new SpriteClass() as Sprite;
trace("sprite2 通过 getDefinitionByName 创建 Sprite 实例");

画一个 100 x 100 的矩形并显示

sprite2.graphics.beginFill(0xFF00FF);
sprite2.graphics.drawRect(0, 0, 100, 100);
sprite2.graphics.endFill();
addChild(sprite2);

修改后的 ReflectionSample.as

package {
    import flash.display.Sprite;
    import flash.utils.getDefinitionByName;
    import flash.utils.getQualifiedClassName;
    import flash.utils.getQualifiedSuperclassName;

    public class ReflectionSample extends Sprite
    {
        public function ReflectionSample () {
            getClassNameSample();
        }

        /**
         * 使用 flash.utils.getQualifiedClassName 和 getQualifiedSuperclassName 获取类名称, 并动态创建该类
         *
         */
        private function getClassNameSample ():void {
            var sprite1:Sprite = new Sprite();
            var classNameOfSprite:String = getQualifiedClassName(Sprite);
            trace("Sprite 的类名 : " + classNameOfSprite);

            var superclassNameOfSprite:String = getQualifiedSuperclassName(Sprite);
            trace("Sprite 的超类 (基类) 类名 : " + superclassNameOfSprite);

            var SpriteClass:Class = getDefinitionByName(classNameOfSprite) as Class;
            var sprite2:Sprite = new SpriteClass() as Sprite;
            trace("sprite2 通过 getDefinitionByName 创建 Sprite 实例");

            sprite2.graphics.beginFill(0xFF00FF);
            sprite2.graphics.drawRect(0, 0, 100, 100);
            sprite2.graphics.endFill();
            addChild(sprite2);
        }

    }
}

获取类信息

QUOTE:
------------------------------------------------------------
public function describeType(value:*):XML
生成一个 XML 对象来描述参数中指定的 ActionScript 对象, 这个方法使 ActionScript 实现了反射编程的概念.

如果参数 value 是某类的实例, 那么返回的 XML 对象包含了此类中所有的实例属性, 但是不会包含任何的静态属性.
这种情况下你可以通过检查标签 <type> 中的 isStatic 属性来判断他, 当参数为某类的实例时, 这个值为 false.

要获取类的静态属性, 可以通过传递类本身到参数 value, 这样返回的 XML 对象不仅包括了类的静态属性, 也包括所有的实例属性.
实例属性被包含在 <factory> 标签中使它们和静态属性区别开来. 在这种情况下, <type> 标签的 isStatic 属性为 true.

提示: 如果你只需要获取对象的继承结构而不需要 describeType() 提供的其他信息, 可以使用 getQualifiedClassName() 和 getQualifiedSuperclassName() 来替代

下表描述了 describeType() 生成的 XML 的标签和属性 (按运行代码察看)

<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd" >

< html >

< head >

< meta http-equiv ="Content-Type" content ="text/html; charset=gb2312" >

< style type ="text/css" >

* { font- size : 1em; }

table, td, th { font-family : Verdana; border : 1px solid #000; border-collapse : collapse; background-color : #fefefe}

th { background-color : #ccc; }

</ style >

</ head >

< body >

< table width ="100%" >

< tr >< th > 标签 </ th >< th > 属性 </ th >< th > 说明 </ th ></ tr >

< tr >< td >< code > < type > </ code ></ td >< td > </ td >< td > XML 对象的根标签 </ td ></ tr >

< tr >< td > </ td >< td > name </ td >< td > ActionScript 对象 (ActionScript object) 类型 </ td ></ tr >

< tr >< td > </ td >< td > base </ td >< td > 当前对象的直属超类, 如果当前 ActionScript 对象是类对象, 那那么该值为 < code > Class </ code > . </ td ></ tr >

< tr >< td > </ td >< td > isDynamic </ td >< td > 如果当前 ActionScript 对象被定义为 dynamic, 那么该属性为 < code > true </ code > , 否则为 < code > false </ code > . 如果当前 ActionScript 对象是类对象, 那么该属性也为 < code > true </ code > , 因为 Class 类是 dynamic 的 </ td ></ tr >

< tr >< td > </ td >< td > isFinal </ td >< td > 如果当前 ActionScript 对象被定义为 final, 那么该属性为 < code > true </ code > , 否则为 < code > false </ code ></ td ></ tr >

< tr >< td > </ td >< td > isStatic </ td >< td > 如果当前 ActionScript 是类对象或者构造函数, 那么该属性为 < code > true </ code > , 否则为 < code > false </ code > . 该属性被命名为 < code > isStatic </ code > 是因为如果值为 < code > true </ code > 的话, 任何标签都不会被嵌套到 < code > factory </ code > 标签中 </ td ></ tr >

< tr >< td >< code > < extendsClass > </ code ></ td >< td > </ td >< td > 使用 < code > extendsClass </ code > 标签分别存放当前 ActionScript 对象的超类 </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 当前 ActionScript 对象所继承的超类的名字 </ td ></ tr >

< tr >< td >< code > < implementsInterface > </ code ></ td >< td > </ td >< td > 使用 < code > implementsInterface </ code > 标签分别存放当前 ActionScript 对象, 以及他的超类所实现的接口 </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 当前 ActionScript 所实现的接口的名字 </ td ></ tr >

< tr >< td >< code > < accessor > </ code ></ td >< td > </ td >< td > 访问器是由 getter 和 setter 所定义的属性 </ td ></ tr >

< tr >< td > </ td >< td > name </ td >< td > 该访问器的名字 </ td ></ tr >

< tr >< td > </ td >< td > access </ td >< td > 该访问器的访问权限. 可能的值有 < code > readonly </ code > , < code > writeonly </ code > , 和 < code > readwrite </ code > . </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 该属性的数据类型 </ td ></ tr >

< tr >< td > </ td >< td > declaredBy </ td >< td > 指示由哪个类定义了该访问器 </ td ></ tr >

< tr >< td >< code > < constant > </ code ></ td >< td > </ td >< td > 常量是由 < code > const </ code > 所定义的属性 </ td ></ tr >

< tr >< td > </ td >< td > name </ td >< td > 该常量的名称 </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 该常量的数据类型 </ td ></ tr >

< tr >< td >< code > < method > </ code ></ td >< td > </ td >< td > 方法是由类定义的一部分公开的函数 </ td ></ tr >

< tr >< td > </ td >< td > name </ td >< td > 方法名 </ td ></ tr >

< tr >< td > </ td >< td > declaredBy </ td >< td > 指示该方法由哪个类定义 </ td ></ tr >

< tr >< td > </ td >< td > returnType </ td >< td > 方法的返回类型 </ td ></ tr >

< tr >< td >< code > < parameter > </ code ></ td >< td > </ td >< td > 使用 < code > parameter </ code > 分别存放该方法的参数, 该标签被嵌套在 < code > < method > </ code > 中 </ td ></ tr >

< tr >< td > </ td >< td > index </ td >< td > 一个数字指示当前参数被传递时所在函数中的位置, 如果是首个参数, 那么该值为 1 </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 该参数的类型 </ td ></ tr >

< tr >< td > </ td >< td > optional </ td >< td > 如果该参数为可选的话为 < code > true </ code > , 否则为 < code > false </ code ></ td ></ tr >

< tr >< td >< code > < variable > </ code ></ td >< td > </ td >< td > 变量 (variable) 是由 var 语句所定义的变量 </ td ></ tr >

< tr >< td > </ td >< td > name </ td >< td > 变量名 </ td ></ tr >

< tr >< td > </ td >< td > type </ td >< td > 变量类型 </ td ></ tr >

< tr >< td >< code > < factory > </ code ></ td >< td > </ td >< td > 如果当前 ActionScript 对象是类对象或者构造函数, 所有的实例属性将会被嵌套进该标签. 如果 < code > < type > </ code > 标签的 < code > isStatic </ code > 属性为 < code > true </ code > , 所有属性 (properties) 和方法 (method) 将不会被嵌套进改标签中. 该标签只出现在当前 ActionScript 对象是类对象或者构造函数的情况下 </ td ></ tr >

</ table >

</ body >

</ html >

另外, 由 describeType() 返回的类描述信息中只会含有所有可被访问的元素, 即所有非定义为 private 的元素.

解释了这么多, 我们来看看返回的 XML 格式
flash 的内置类 flash.display.Sprite :

trace(describeType(Sprite);

< type name ="flash.display::Sprite" base ="Class" isDynamic ="true" isFinal ="true" isStatic ="true" >

< extendsClass type ="Class" />

< extendsClass type ="Object" />

< accessor name ="prototype" access ="readonly" type ="*" declaredBy ="Class" />

< factory type ="flash.display::Sprite" >

< extendsClass type ="flash.display::DisplayObjectContainer" />

< extendsClass type ="flash.display::InteractiveObject" />

< extendsClass type ="flash.display::DisplayObject" />

< extendsClass type ="flash.events::EventDispatcher" />

< extendsClass type ="Object" />

< implementsInterface type ="flash.display::IBitmapDrawable" />

< implementsInterface type ="flash.events::IEventDispatcher" />

< accessor name ="hitArea" access ="readwrite" type ="flash.display::Sprite" declaredBy ="flash.display::Sprite" />

< method name ="startDrag" declaredBy ="flash.display::Sprite" returnType ="void" >

< parameter index ="1" type ="Boolean" optional ="true" />

< parameter index ="2" type ="flash.geom::Rectangle" optional ="true" />

</ method >

< accessor name ="buttonMode" access ="readwrite" type ="Boolean" declaredBy ="flash.display::Sprite" />

< accessor name ="graphics" access ="readonly" type ="flash.display::Graphics" declaredBy ="flash.display::Sprite" />

< accessor name ="soundTransform" access ="readwrite" type ="flash.media::SoundTransform" declaredBy ="flash.display::Sprite" />

< method name ="stopDrag" declaredBy ="flash.display::Sprite" returnType ="void" />

< accessor name ="dropTarget" access ="readonly" type ="flash.display::DisplayObject" declaredBy ="flash.display::Sprite" />

< accessor name ="useHandCursor" access ="readwrite" type ="Boolean" declaredBy ="flash.display::Sprite" />

< method name ="getChildAt" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="int" optional ="false" />

</ method >

< method name ="addChild" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< method name ="swapChildren" declaredBy ="flash.display::DisplayObjectContainer" returnType ="void" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

< parameter index ="2" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< method name ="getChildByName" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="String" optional ="false" />

</ method >

< method name ="getObjectsUnderPoint" declaredBy ="flash.display::DisplayObjectContainer" returnType ="Array" >

< parameter index ="1" type ="flash.geom::Point" optional ="false" />

</ method >

< accessor name ="textSnapshot" access ="readonly" type ="flash.text::TextSnapshot" declaredBy ="flash.display::DisplayObjectContainer" />

< method name ="removeChildAt" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="int" optional ="false" />

</ method >

< method name ="getChildIndex" declaredBy ="flash.display::DisplayObjectContainer" returnType ="int" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< method name ="areInaccessibleObjectsUnderPoint" declaredBy ="flash.display::DisplayObjectContainer" returnType ="Boolean" >

< parameter index ="1" type ="flash.geom::Point" optional ="false" />

</ method >

< accessor name ="mouseChildren" access ="readwrite" type ="Boolean" declaredBy ="flash.display::DisplayObjectContainer" />

< method name ="removeChild" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< method name ="setChildIndex" declaredBy ="flash.display::DisplayObjectContainer" returnType ="void" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

< parameter index ="2" type ="int" optional ="false" />

</ method >

< method name ="contains" declaredBy ="flash.display::DisplayObjectContainer" returnType ="Boolean" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< method name ="addChildAt" declaredBy ="flash.display::DisplayObjectContainer" returnType ="flash.display::DisplayObject" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

< parameter index ="2" type ="int" optional ="false" />

</ method >

< accessor name ="numChildren" access ="readonly" type ="int" declaredBy ="flash.display::DisplayObjectContainer" />

< method name ="swapChildrenAt" declaredBy ="flash.display::DisplayObjectContainer" returnType ="void" >

< parameter index ="1" type ="int" optional ="false" />

< parameter index ="2" type ="int" optional ="false" />

</ method >

< accessor name ="tabChildren" access ="readwrite" type ="Boolean" declaredBy ="flash.display::DisplayObjectContainer" />

< accessor name ="tabEnabled" access ="readwrite" type ="Boolean" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="doubleClickEnabled" access ="readwrite" type ="Boolean" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="contextMenu" access ="readwrite" type ="flash.ui::ContextMenu" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="accessibilityImplementation" access ="readwrite" type ="flash.accessibility::AccessibilityImplementation" declaredBy ="flash.display::InteractiveObject" >

< metadata name ="Inspectable" >

< arg key ="environment" value ="none" />

</ metadata >

</ accessor >

< accessor name ="mouseEnabled" access ="readwrite" type ="Boolean" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="focusRect" access ="readwrite" type ="Object" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="tabIndex" access ="readwrite" type ="int" declaredBy ="flash.display::InteractiveObject" />

< accessor name ="mask" access ="readwrite" type ="flash.display::DisplayObject" declaredBy ="flash.display::DisplayObject" />

< accessor name ="scaleX" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="scaleY" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< method name ="getRect" declaredBy ="flash.display::DisplayObject" returnType ="flash.geom::Rectangle" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< accessor name ="mouseY" access ="readonly" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="alpha" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="x" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="name" access ="readwrite" type ="String" declaredBy ="flash.display::DisplayObject" />

< accessor name ="y" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="root" access ="readonly" type ="flash.display::DisplayObject" declaredBy ="flash.display::DisplayObject" />

< accessor name ="width" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< accessor name ="stage" access ="readonly" type ="flash.display::Stage" declaredBy ="flash.display::DisplayObject" />

< accessor name ="loaderInfo" access ="readonly" type ="flash.display::LoaderInfo" declaredBy ="flash.display::DisplayObject" />

< accessor name ="transform" access ="readwrite" type ="flash.geom::Transform" declaredBy ="flash.display::DisplayObject" />

< accessor name ="height" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< method name ="localToGlobal" declaredBy ="flash.display::DisplayObject" returnType ="flash.geom::Point" >

< parameter index ="1" type ="flash.geom::Point" optional ="false" />

</ method >

< accessor name ="filters" access ="readwrite" type ="Array" declaredBy ="flash.display::DisplayObject" />

< accessor name ="blendMode" access ="readwrite" type ="String" declaredBy ="flash.display::DisplayObject" />

< accessor name ="rotation" access ="readwrite" type ="Number" declaredBy ="flash.display::DisplayObject" />

< method name ="hitTestObject" declaredBy ="flash.display::DisplayObject" returnType ="Boolean" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< accessor name ="scale9Grid" access ="readwrite" type ="flash.geom::Rectangle" declaredBy ="flash.display::DisplayObject" />

< accessor name ="accessibilityProperties" access ="readwrite" type ="flash.accessibility::AccessibilityProperties" declaredBy ="flash.display::DisplayObject" />

< accessor name ="scrollRect" access ="readwrite" type ="flash.geom::Rectangle" declaredBy ="flash.display::DisplayObject" />

< accessor name ="cacheAsBitmap" access ="readwrite" type ="Boolean" declaredBy ="flash.display::DisplayObject" />

< method name ="globalToLocal" declaredBy ="flash.display::DisplayObject" returnType ="flash.geom::Point" >

< parameter index ="1" type ="flash.geom::Point" optional ="false" />

</ method >

< method name ="getBounds" declaredBy ="flash.display::DisplayObject" returnType ="flash.geom::Rectangle" >

< parameter index ="1" type ="flash.display::DisplayObject" optional ="false" />

</ method >

< accessor name ="opaqueBackground" access ="readwrite" type ="Object" declaredBy ="flash.display::DisplayObject" />

< accessor name ="parent" access ="readonly" type ="flash.display::DisplayObjectContainer" declaredBy ="flash.display::DisplayObject" />

< method name ="hitTestPoint" declaredBy ="flash.display::DisplayObject" returnType ="Boolean" >

< parameter index ="1" type ="Number" optional ="false" />

< parameter index ="2" type ="Number" optional ="false" />

< parameter index ="3" type ="Boolean" optional ="true" />

</ method >

< accessor name ="visible" access ="readwrite" type ="Boolean" declaredBy ="flash.display::DisplayObject" />

< accessor name ="mouseX" access ="readonly" type ="Number" declaredBy ="flash.display::DisplayObject" />

< method name ="willTrigger" declaredBy ="flash.events::EventDispatcher" returnType ="Boolean" >

< parameter index ="1" type ="String" optional ="false" />

</ method >

< method name ="removeEventListener" declaredBy ="flash.events::EventDispatcher" returnType ="void" >

< parameter index ="1" type ="String" optional ="false" />

< parameter index ="2" type ="Function" optional ="false" />

< parameter index ="3" type ="Boolean" optional ="true" />

</ method >

< method name ="toString" declaredBy ="flash.events::EventDispatcher" returnType ="String" />

< method name ="addEventListener" declaredBy ="flash.events::EventDispatcher" returnType ="void" >

< parameter index ="1" type ="String" optional ="false" />

< parameter index ="2" type ="Function" optional ="false" />

< parameter index ="3" type ="Boolean" optional ="true" />

< parameter index ="4" type ="int" optional ="true" />

< parameter index ="5" type ="Boolean" optional ="true" />

</ method >

< method name ="dispatchEvent" declaredBy ="flash.events::EventDispatcher" returnType ="Boolean" >

< parameter index ="1" type ="flash.events::Event" optional ="false" />

</ method >

< method name ="hasEventListener" declaredBy ="flash.events::EventDispatcher" returnType ="Boolean" >

< parameter index ="1" type ="String" optional ="false" />

</ method >

</ factory >

</ type >

真是又臭又长啊. :o, 根据帮助中的描述, 所有的实例属性都被嵌套在了 <factory> 标签里.

我们再试一下获取实例的信息 :

var sprite1:Sprite = new Sprite();
var instanceInfo:XML = describeType(sprite1);

< type name ="flash.display::Sprite" base ="flash.display::DisplayObjectContainer" isDynamic ="false" isFinal ="false" isStatic ="false" >