MACROMEDIA FLASH 8-LEARNING ACTIONSCRIPT 2.0 IN FLASH, Руководство пользователя

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284 Classes
To understand scope and external class files:
1.
Select File > New and then select ActionScript File, and then click OK.
2.
Type or paste the following code into the Script window:
/**
Product class
Product.as
*/
class Product {
private var productsXml:XML;
// constructor
// targetXmlStr - string, contains the path to an XML file
function Product(targetXmlStr:String) {
/* Create a local reference to the current class.
Even if you are within the XML's onLoad event handler, you
can reference the current class instead of only the XML packet.
*/
var thisObj:Product = this;
// Create a local variable, which is used to load the XML file.
var prodXml:XML = new XML();
prodXml.ignoreWhite = true;
prodXml.onLoad = function(success:Boolean) {
if (success) {
/* If the XML successfully loads and parses,
set the class's productsXml variable to the parsed
XML document and call the init function.
*/
thisObj.productsXml = this;
thisObj.init();
} else {
/* There was an error loading the XML file. */
trace("error loading XML");
}
};
// Begin loading the XML document.
prodXml.load(targetXmlStr);
}
public function init():Void {
// Display the XML packet.
trace(this.productsXml);
}
}
Because you are trying to reference the private member variable within an
onLoad
handler,
the
this
keyword actually refers to the
prodXml
instance and not the Product class, which
you might expect. For this reason, you must create a pointer to the local class file so that
you can directly reference the class from the
onLoad
handler. You can now use this class
with a Flash document.