Flex如何计算加载时间

Flex中有Preloader关键字，可以为其指派一个preload类，用于管理Flex应用Loading期间的逻辑，包括计算加载时间、定制加载动画、定制加载进度条等。

To make a custom preloader for Flex, you have to do 2 steps:

1. Write a class that extendsDownloadProgressBar
2. Set thepreloader propertyon your Application class to your preloader class.

参考：

http://www.cnblogs.com/ternastone/archive/2010/12/06/1897641.html

http://jessewarden.com/2007/07/making-a-cooler-preloader-in-flex-part-1-of-3.html

关键字：preloader， downloadProgressBar，Flex加载