How to load and apply a CSS stylesheet at runtime in a Flex application?

Question

I'd like to load CSS stylesheets from a URL and apply them to my Flex 3 application at runtime. Is it possible?

Answer 1

You cannot load an uncompiled CSS file into your Flex application at run time. You must compile it into a SWF file before loading it. - Adobe Flex 3 Docs

You can load style sheets (compiled) using the Style Manager.

For the full run-down : Loading style sheets at run time

Answer 2

You can load css files at runtime to style the text in a TextField.

var loader:URLLoader = new URLLoader();
var req:URLRequest = new URLRequest("style.css");
loader.load(req);
loader.addEventListener(Event.COMPLETE, completeHandler);

private function completeHandler(e:Event):void 
{
  var css:StyleSheet = new StyleSheet();
  css.parseCSS(e.target.data);
  yourTextField.styleSheet = css;
}

As for styling controls, I'm afraid you can't load a text file at run time. May be you can parse it using the StyleSheet class - check out the styleNames array and the getStyle method.