XUL is an XML variant that can be used to create application user interfaces. It can also be used as an element in creating entire applications. This article, the first in a series, introduces you to the idea and helps you get your system ready to start creating.
Back to XUL: Introduction and Preparation - Setting up your system for running XUL applications (Page 3 of 4 )
As I mentioned above, there are two ways in which XUL applications can be run. One is within Mozilla, in the same way that a web page would be displayed in the main content window. The second way allows standalone applications to be executed using the command line; the application will then appear in its own independent window, but as the splash-screen shows when you run it, it will still be powered by Mozilla.
Neither option is any easier or harder to construct, as the code used within each is the same. When creating programs designed to run within Mozilla, however, Mozilla itself kind of takes over as the main application and any keyboard shortcuts for menus in your application won’t work. For example, if you create a File menu with the standard Alt + F keyboard shortcut, when you press Alt + F, Mozilla’s file menu will open instead of your own. To avoid this and other subtle pitfalls, we will run the application within its own window.
This makes setting up your system for XUL a little more complicated because you have to add a system environment variable telling your computer what to do when XUL files are executed. Clearly, Mozilla needs to be installed on your system in order to follow this tutorial. I am using the latest version of the browser; at the time of writing that is version 1.7.12, on Windows XP Pro SP2.
Once installed, go to your Control Panel and open the System applet. Once the System dialog box opens, select the Advanced tab and hit the Environment Variables button. When the Environment Variables dialog box opens, find the Path variable and add the following line of code to the end of it:
Once this has been done (and your files have been registered of course), you can launch your application with the following command:
Mozilla –chrome chrome://nameofyourapp/content
You can create a XUL folder at this point on your C: drive to store the files that are going to be created in order to make the application work. Now create an application folder within that called XULEditLite, and then in that folder create a locale, skin and content folder:
The content folder is going to be used to store the main XUL and script file(s). The skin file is where button icons, other graphics, and style sheets separate from the main ones are kept. The skins are segregated into their own directory to make it easier for people to add their own themes to your application. Additionally, most developers now separate their applications in this way to provide a presentation layer separate from the main application layer, so that’s exactly what you should do too. Finally, the locale folder is used to store DTDs that contain the labels and other text strings from the labels used in your application; within this folder, you should also create a folder called en-US.