MACROMEDIA COLDFUSION MX 7.0.2-USING COLDFUSION MX WITH FLEX 2 Guide de l'utilisateur télécharger pdf (Page 112)

112 Retrieve and Display Data

Insert a HTTPService component

For the blog reader in this lesson, you retrieve posts from Matt Chotin’s blog at http://

www.adobe.com/go/mchotinblog on a news aggregator website. Matt is a product manager

on the Flex team and writes about Flex in his blog.

You can use the HTTPService component to access the blog’s XML feed and retrieve

information about recent posts. The component lets you send an HTTP GET or POST

request, and then retrieve the data returned in the response.

1. In Source mode, enter the following <mx:HTTPService> tag immediately after the opening

<mx:Application> tag:

<mx:HTTPService

id="feedRequest"

url="http://weblogs.macromedia.com/mchotin/index.xml"

useProxy="false"/>

The url property specifies the location of the requested file, in this case the RSS 2.0 feed

of Matt Chotin’s blog. As of this writing, the URL was still valid, but you should check to

make sure it hasn’t changed. You should use the latest RSS 2.0 URL listed on the right side

of the blog at http://www.adobe.com/go/mchotinblog.

The

useProxy property specifies that you don’t want to use a proxy on a server. The

domain where Matt’s blog is located has a crossdomain.xml setup, so Flash Player can

access the remote data sources on this server, including RSS feeds. For more information,

see “Review your access to remote data sources” on page 108.

The next step is to prompt the application to send a request to the specified URL. You

decide to send the request automatically whenever the application starts, as follows.

2. In the <mx:Application> tag, add the following creationComplete property (in bold):

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

layout="absolute" creationComplete="feedRequest.send()">

When your application is finished starting up, the HTTPService component’s send()

method is called. The method makes an HTTP GET or POST request to the specified

URL, and an HTTP response is returned. In this case, the RSS feed returns XML data.

Next, you want to check if the application is retrieving the RSS feed successfully. You can

do this by binding data to the Label control, as follows.

NOTE

If you want, you can also use the following alias in the component: http://

www.adobe.com/go/flex_blogfeed.

1 2 ... 107 108 109 110 111 112 113 114 115 116 117 ... 255 256

Pas de commentaire

MACROMEDIA COLDFUSION MX 7.0.2-USING COLDFUSION MX WITH FLEX 2 Guide de l'utilisateur Page 112