mx.core.UIComponentDescriptor - Adobe® Flex® 4 Language Reference (Flex 4)

Package	mx.core
Class	public class UIComponentDescriptor
Inheritance	UIComponentDescriptor ComponentDescriptor Object

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

A UIComponentDescriptor instance encapsulates the information that you specified in an MXML tag for an instance of a visual component.

Most of the tags in an MXML file describe a tree of UIComponent objects. For example, the <mx:Application> tag represents a UIComponent object, and its child containers and controls are all UIComponent objects.

The MXML compiler compiles each of these MXML tags into a UIComponentDescriptor instance. To be precise, the MXML compiler autogenerates an ActionScript data structure which is a tree of UIComponentDescriptor objects.

At runtime, the createComponentsFromDescriptors() method of the Container class uses the information in the UIComponentDescriptor objects in the container's childDescriptors array to create the actual UIComponent objects that are the container's children, plus deeper descendants as well. Depending on the value of the container's creationPolicy, property, the descendants might be created at application startup, when some part of the component is about to become visible, or when the application developer manually calls the createComponentsFromDescriptors() method.

You do not typically create UIComponentDescriptor instances yourself; you can access the ones that the MXML compiler autogenerates via the childDescriptors array of the Container class.

Public Properties

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	Property		Defined By
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		document : Object A reference to the document Object in which the component is to be created.	ComponentDescriptor
		effects : Array An Array containing the effects for the component, as specified in MXML.	UIComponentDescriptor
		events : Object An Object containing name/value pairs for the component's event handlers, as specified in MXML.	ComponentDescriptor
		id : String The identifier for the component, as specified in MXML.	ComponentDescriptor
		properties : Object [read-only] An Object containing name/value pairs for the component's properties, as specified in MXML.	ComponentDescriptor
		propertiesFactory : Function A Function that returns an Object containing name/value pairs for the component's properties, as specified in MXML.	ComponentDescriptor
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		stylesFactory : Function A Function that constructs an Object containing name/value pairs for the instance styles for the component, as specified in MXML.	UIComponentDescriptor
		type : Class The Class of the component, as specified in MXML.	ComponentDescriptor

Public Methods

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	Method		Defined By
		UIComponentDescriptor(descriptorProperties:Object) Constructor.	UIComponentDescriptor
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		invalidateProperties():void Invalidates the cached properties property.	ComponentDescriptor
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string "ComponentDescriptor_" plus the value of the id property.	ComponentDescriptor
		valueOf():Object Returns the primitive value of the specified object.	Object

Property Detail

effects

property

public var effects:Array

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

An Array containing the effects for the component, as specified in MXML.

For example, if you write the following code:

	  <mx:TextInput showEffect="Fade" hideEffect="Fade"/>

The descriptor's effects property is the Array [ "showEffect", "hideEffect" ].

The effectsproperty is null if no MXML effects were specified for the component.

Note that the values of the effect attributes are not specified in this property. Instead, effects are treated like styles and therefore are include in the stylesFactory property. The effect Array simply keeps track of which styles in the stylesFactory are actually effects.

This property is used by the Container method createComponentsFromDescriptors() to register the effects with the EffectManager.

stylesFactory

property

public var stylesFactory:Function

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

A Function that constructs an Object containing name/value pairs for the instance styles for the component, as specified in MXML.

For example, if you write the following code:

	  <mx:TextInput borderColor="0x888888" color="0xDDDDDD"/>

Then the descriptors' stylesFactory property is the Function:

	  function():void { this.borderColor = 0x888888; this.color = 0xDDDDDD };

The stylesFactory property is null if no MXML styles were specified for the component instance.

Constructor Detail

UIComponentDescriptor

()

Constructor

public function UIComponentDescriptor(descriptorProperties:Object)

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Constructor.

Parameters

descriptorProperties:Object — An Object containing name/value pairs for the properties of the UIComponentDescriptor object, such as its type, id, propertiesFactory, events, stylesFactory, and effects.