Dynamic, Static and Predefined Styles

J2ME Polish distinguishes between dynamic, static and predefined styles:

• Predefined styles are used by the GUI for several items like screen-titles.
• Static styles are defined in the source code of the application with the #style preprocessing directive.
• Dynamic styles are used for items according to their position on the screen.

Static Styles

The easiest styles are the static ones. The programmer just needs to tell the designer the style names and what they are used for (that is for what kind of items or screens) and the designer defines them in the appropriate polish.css file. Static styles always start with a dot, e.g. ".myStyle". Static styles are faster than dynamic styles. It is therefore recommended to use static styles whenever possible.

Predefined Styles

Predefined styles are static styles which are used by the J2ME Polish GUI. In contrast to the normal "user-defined" static styles their names do not start with a dot, e.g. "title" instead of ".title". Following predefined styles are used:

<variable name="polish.usePolishTitle" value="true" unless="polish.Vendor == Nokia" />

The names of predefined styles must not be used for static styles, so you must not use a static style with the name ".title" etc.

Dynamic Styles

Dynamic styles can be used to apply styles to items without using #style directives in the source code. With dynamic styles the designer can work completely independent of the programmer and try out new designs for GUI items which have not yet an associated static style. You can also check out the power and possibilities of the J2ME Polish API without changing the source code of an existing application at all. Obviously, dynamic styles need a bit more memory and processing time than static styles. It is recommended, therefore, to use static styles instead for finished applications. Dynamic styles do not start with a dot and use the selectors of the items they want to design: Texts use either "p", "a", "button" or "icon". Screens use the name of the screen, e.g. "form", "list" or "textbox".

p {
	font-color: black;
	font-size: medium;
	background: none;
}
form {
	margin: 5;
	background-color: gray;
	border: none;
	font-size: medium;
}

You can also design only items which are contained in other items or screens: The style "form p" designs all text-items (of the class StringItem) which are contained in a form:

form p {
	font-color: white;
	font-size: medium;
}

Static styles and dynamic styles can be used together, you can design all hyperlinks1 in the screen with the style ".startScreen" for example with the following style declaration:

.startScreen a {
	font-color: blue;
	font-size: medium;
	font-style: italic;
}

Items and screens have specific selectors for dynamic styles: