At Adobe MAX this year, I got an idea for an interesting little Flex component. It took me a while to get around to implementing it, but I finally found some time. At the time, I had been building several quick prototype applications with floating information windows that needed to be added to the PopUpManager immediately when the application was initialized. Seeing as these were prototypes, I wanted to be able to do this rapidly without making new class files for each window, and if possible, I’d like to skip calling any methods on PopUpManager from a Script block. Basically, I wanted to throw as much as possible into one MXML file, and then have some component that’s smart enough to add my components to the PopUpManager. With those requirements in mind, the PopUpInitializer was born.

Here’s some example code that adds a TitleWindow to the PopUpManager using PopUpInitializer:

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

    <toolbox:PopUpInitializer>
        <mx:TitleWindow title="An Example Pop-Up"
            x="50" y="50" width="200" height="200"/>
    </toolbox:PopUpInitializer>

</mx:Application>

It’s a simple class that implements IMXMLObject and makes liberal use of compiler metadata to make itself act like a regular UI container. For example, it uses the [DefaultProperty] metadata to pass the UIComponents to a controls property without having to specify that property name, and the [ArrayElementType] metadata to specify that the controls (there may be more than one) must all be of type mx.core.IUIComponent. Once it receives the list of controls, it waits for the application to be created, and then tosses them all up on the PopUpManager. A cleanup() method is added for convenience to remove all the controls from the PopUpManager, if desired.

Download the component SWC, an example, and the full source code from my Google Code repository. API documentation for PopUpInitializer is available as part of the common documentation with my other “Flex Toolbox” controls like ZoomFrame and PopUpThumbnail. As with most of my other open source code, PopUpInitializer is available under the terms of an MIT-style license.