AS3中的反射(2)
获取类信息
QUOTE:
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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)
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标签 属性 说明
<type> XML 对象的根标签
name ActionScript 对象 (ActionScript object) 类型
base 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 Class.
isDynamic 如果当前 ActionScript 对象被定义为 dynamic, 那么该属性为 true, 否则为 false. 如果当前 ActionScript 对象是类对象, 那么该属性也为 true, 因为 Class 类是 dynamic 的
isFinal 如果当前 ActionScript 对象被定义为 final, 那么该属性为 true, 否则为 false
isStatic 如果当前 ActionScript 是类对象或者构造函数, 那么该属性为 true, 否则为 false. 该属性被命名为 isStatic 是因为如果值为 true 的话, 任何标签都不会被嵌套到 factory 标签中
<extendsClass> 使用 extendsClass 标签分别存放当前 ActionScript 对象的超类
type 当前 ActionScript 对象所继承的超类的名字
<implementsInterface> 使用 implementsInterface 标签分别存放当前 ActionScript 对象, 以及他的超类所实现的接口
type 当前 ActionScript 所实现的接口的名字
<accessor> 访问器是由 getter 和 setter 所定义的属性
name 该访问器的名字
access 该访问器的访问权限. 可能的值有 readonly, writeonly, 和 readwrite.
type 该属性的数据类型
declaredBy 指示由哪个类定义了该访问器
<constant> 常量是由 const 所定义的属性
name 该常量的名称
type 该常量的数据类型
<method> 方法是由类定义的一部分公开的函数
name 方法名
declaredBy 指示该方法由哪个类定义
returnType 方法的返回类型
<parameter> 使用 parameter 分别存放该方法的参数, 该标签被嵌套在 <method> 中
index 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
type 该参数的类型
optional 如果该参数为可选的话为 true, 否则为 false
<variable> 变量 (variable) 是由 var 语句所定义的变量
name 变量名
type 变量类型
<factory> 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 <type> 标签的 isStatic 属性为 true, 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
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);
返回:
<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">
<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>
</type>
所有的标签与之前 factory 标签中的内容是一样的
现在我们使用 describeType 来遍历之前 Dummy 类中的元素
实例化:
var dummy:Dummy = new Dummy();
获取实例信息:
var instanceInfo:XML = describeType(dummy);
把所有的属性取出来, 包括访问器和变量, 并且访问器不可为只写:
var properties:XMLList = instanceInfo..accessor.(@access != "writeonly") + instanceInfo..variable;
此时 properties 里就有所有的属性名了. 最后我们遍历这个 XMLList
for each (var propertyInfo:XML in properties) {
// 取出属性名
var propertyName:String = propertyInfo.@name;
// 根据属性名来访问
trace(dummy[propertyName]);
}
这样 dummy 就被 "遍历" 出了~
完整代码:
var dummy:Dummy = new Dummy();
var instanceInfo:XML = describeType(dummy);
var properties:XMLList = instanceInfo..accessor.(@access != "writeonly") + instanceInfo..variable;
for each (var propertyInfo:XML in properties) {
var propertyName:String = propertyInfo.@name;
trace(dummy[propertyName]);
}
这样我们可以专门写一个类, 负责获取类信息, 详细见类中注释
TypeDescriptor.as, 负责获取信息
package
{
import flash.utils.describeType;
import flash.utils.getQualifiedClassName;
import flash.utils.getDefinitionByName;
/**
* 使用 flash.utils.describeType 获取类详细信息并缓存
* @author kakera
*
*/
public class TypeDescriptor
{
/**
* 缓存已经反射过了的对象
*/
private static var typeCache:Object = new Object();
/**
* 获取类信息
* @param target 要获取的目标对象
* @return TypeDescriptorEntry 实例
*
*/
public static function describeType (target:*):TypeDescription {
var className:String = getQualifiedClassName(target);
/**
* 检查缓存中是否已经有目标对象项, 如果有就返回缓存中的内容
*/
if (className in typeCache)
return typeCache[className];
/**
* 暂存属性列表
*/
var propertyNames:Array = [];
/**
* 获取类信息, 如果传入的是实例则获取实例类型的类信息
*/
var typeInfo:XML = flash.utils.describeType(target is Class ? target : getDefinitionByName(className) as Class);
/**
* 获取类中所有的属性和访问器
*/
var properties:XMLList = typeInfo.factory..accessor.(@access != "writeonly") + typeInfo..variable;
/**
* 遍历并存放到 propertyNames 中
*/
for each (var propertyInfo:XML in properties)
propertyNames.push(propertyInfo.@name);
/**
* 创建 TypeDescriptorEntry 的实例并把 propertyNames 等属性丢进去
*/
var entry:TypeDescription = new TypeDescription();
entry.name = className;
entry.properties = propertyNames;
entry.typeInfo = typeInfo;
/**
* 缓存到 typeCache 中以便下次从缓存中读取
*/
typeCache[className] = entry;
return entry;
}
/**
* 静态类无须实例化
* @return
*
*/
public function TypeDescriptor () { }
}
}
TypeDescription.as, 负责保存信息
package
{
public class TypeDescription
{
/**
* 类的属性列表, 包括访问器 (accessor) 和变量 (variable)
*/
public var properties:Array; /* of String */
/**
* 类名
*/
public var name:String;
/**
* 由 flash.utils.describeType() 获取的原始 XML 数据
*/
public var typeInfo:XML;
public function TypeDescription () { }
}
}
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