ScaleNine

With Flex 3 there are a lot of great new features to help streamline the implementation of your custom skins into your Flex or AIR application. One of them is the Flex Skin Design Extensions (SDE) for Flash, Illustrator, Photoshop and Fireworks. These were available during the beta releases of Flex 3, so you may already be familiar with it. However, since the full release of Flex 3 there have been some updates to the extensions and I wanted to point out a few tricks that may help streamline your skinning workflow a bit further. Also, if you’re new to skinning Flex apps, check out Narciso Jaramillo’s updated article about creating skins for Flex using Adobe Creative Suite 3.

Naming Conventions

If you look at the skin templates that come with the Flex SDE you’ll notice that each skin is named in a particular way. The naming convention works by specifying the component name, an underscore “_”, then the component skin part. For example, Button_upSkin, Button_overSkin, etc. They are named this way so when you import the skin through Flex Builder’s Skin Import Wizard the combo boxes that allow you to assign a skin state for each skin are “automagically” assigned to the skin state you specified in the skin template. This is good to know because you can use the same naming conventions when you’re making your own custom skins that may be created without using the templates provided. I typically make a single file with all my skins in it and use this naming convention frequently.

This method will work for a variety of scenarios. For example, if you need to add a background image to a certain container, you could use myVbox_backgroundImage and it will go through the Skin Import Wizard very easily. This will work for other “skinnable” parts, like borderSkin, upIcon, etc. Easy enough, right?

The other nice thing you can do with adhering to these naming conventions is skin “sub-components”. For example, the DateField component allows you to specify a textInputStyleName. You can assign skins to that text input by specifying the component name, adding a hypen “-” (Illustrator, Fireworks, Illustrator) or dollar sign “$” (Flash) with the sub-component name, then and underscore “_” and the sub-component skin part. So, in the case of the DateField, you could specify the borderSkin for the text input like this:

DateField-textInput_borderSkin (Illustrator, Fireworks, Photoshop) or DateField$textInput_borderSkin (Flash)

Notice I just used “textInput” and not “textInputStyleName”. This is because “StyleName” is appended to the sub-component name during the Skin Import process in Flex. For example, naming a skin asset in Flash “ComboBox$dropdown_backgroundImage”, publishing it and importing it using the Skin Import Wizard would produce the following CSS (Note: You’d have to add backgroundSize: ‘100%’ for the image to stretch.):

ComboBox
{
dropdownStyleName: “comboBoxDropdown“;
}
.comboBoxDropdown
{
backgroundImage: Embed(skinClass=“ComboBox$dropdown_backgroundImage“);
}

If you look at the skin template for the application your using you should see this naming convention used for the tab skins. You can use this same naming convention for other sub-components, like dropdown, verticalScrollBar, etc. Just naming your skin assets a certain way can really streamline the the skin production process.

Naming for CSS Design Mode Previews

Another new feature in Flex 3 is CSS Design Mode. While viewing CSS you can click on the “Design” mode button to see what your CSS looks like applied to a particular component. However, if you were to create a style class and switch to CSS Design Mode you won’t get an immediate preview. This is because you have to specify a component to preview the CSS against. A way to forego this step is to add the type of component you want the styling applied to to the class name. For example, if I had a class name of “blueButton” I could preview it as a Button component in CSS Design Mode by adding “Button” to the class name keeping the dot “.” of the class name like this:

Button.myButton
{
fillAlphas: 1.0, 1.0;
fillColors: #84B1F4, #1D4888;
borderColor: #07314F;
color: #FFFFFF;
}

This will work for pretty much any component, provide a quick way to preview the CSS styling on a component without having to specify it in CSS Design Mode and make your CSS a bit more descriptive. If you use the same styling across multiple components you may want to leave class names void of component specifications.

Other Resources

Designing Flex 3 skins and styles using Creative Suite 3 and Flex Builder 3
Flex 3 CSS Design Mode in LiveDocs

This entry was posted on Sunday, March 16th, 2008 at 12:00 pm and is filed under css, how-to, tips, tools, workflow. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.