Specifications

CHAPTER 5

102

In this example, the image on the left shows the application after the first container is populated with its children

and data, but before the remaining four containers are populated. The image on the right shows the final state of

the application.

If this application did not use ordered creation, Flex would not display anything until all components in all five of

the containers were created, resulting in a longer perceived start-up time.

To gradually display children of each container, you add them to an instantiation queue. The “Adding containers

to the queue” on page 102 section describes how to add containers to the queue so that you can improve perceived

layout performance of your Flex applications.

Adding containers to the queue

You can add any number of containers to the instantiation queue so that their contents are displayed in queue

order. To add a container to the instantiation queue, you set the value of the container’s

creationPolicy property

queued. Unless you specify a queue order, containers are instantiated and displayed in the order in which they

appear in the application source code.

In the following example, the Panel containers and their child controls are added to the instantiation queue. To

the user, each Panel container appears one at a time during the application startup. The perceived startup time of

the application is greatly reduced. The panels are created in the order that they appear in the source code (panel1,

panel2, panel3):

<?xml version="1.0"?>

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

<mx:Panel id="panel1" creationPolicy="queued" width="100%" height="33%">

<mx:Button id="button1a" label="Button 1A"/>

<mx:Button id="button1b" label="Button 1B"/>

</mx:Panel>

<mx:Panel id="panel2" creationPolicy="queued" width="100%" height="33%">

<mx:Button id="button2a" label="Button 2A"/>