Adobe FLEX 2 - CREATING AND EXTENDING COMPONENTS, Руководство пользователя

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200 Creating Template Components
The following example shows an alternative implementation for the MyTemplateComponent
component shown in the section
“About template components” on page 195 , named
MyTemplateComponentDeferred.mxml, by defining the topRow and bottomRow properties
to be of type
IDeferredInstance :
<?xml version="1.0"?>
<!-- templating/myComponents/MyTemplateComponentDeferred.mxml -->
<mx:VBox xmlns:mx="http://www.adobe.com/2006/mxml"
initialize="init();">
<mx:Script>
<![CDATA[
import mx.containers.HBox;
import mx.core.UIComponent;
// Define a deferred property for the top component.
public var topRow:IDeferredInstance;
// Define an Array of deferred properties
// for a row of components.
[ArrayElementType("mx.core.IDeferredInstance")]
public var bottomRow:Array;
private function init():void {
// Add the top component to the VBox container.
// Cast the IDeferredInstance object to UIComponent
// so that you can add it to the parent container.
addChild(UIComponent(topRow.getInstance()));
// Create an HBox container. This container
// is the parent container of the bottom row of components.
var controlHBox:HBox = new HBox();
// Add the bottom row of components
// to the HBox container.
for (var i:int = 0; i < bottomRow.length; i++)
controlHBox.addChild(UIComponent(bottomRow[i].getInstance()));
// Add the HBox container to the VBox container.
addChild(controlHBox);
}
]]>
</mx:Script>
</mx:VBox>
The IDeferredInstance interface defines a single method,
getInstance()
. Flex calls the
getInstance()
method to initialize a property when it creates an instance of the component.
A subsequent call to the
getInstance()
method returns a reference to the property value.