SWT: A Developer's Notebook

Working with Shell Styles

Windows come in all types, shapes, and sizes. Some have titlebars, some don’t. Some have minimize, maximize, and close buttons, and some don’t. You need some way to control the appearance of windows, and with the SWT Shell class, you do that by using a second constructor that enables you to pass a style— an integer value the class uses to determine what attributes to show or hide.

How do I do that?

To specify a style for a shell, the SWT provides us with a set of enumerated values encapsulated in another class called SWT. The SWT class is located in the org.eclipse.swt package. For shells, the enumerated values are BORDER , CLOSE, MIN, MAX, NO_TRIM, RESIZE, and TITLE. Also, two convenience values—SHELL_TRIM and DIALOG_TRIM —combine several of the style attributes to create two common looks for windows.

The Shell class has multiple constructors. You utilized one of those earlier when you created an instance of your first shell:

Shell s = new Shell(d);

This constructor accepted only an instance of the Display class as an argument. To open an instance of Shell that accepts a style value, you must use a different constructor:

Shell(Display display, int style)

As you can see from this constructor’s prototype, you are permitted to pass in only a single int value to control all the attributes. This means that you must have some way to combine the enumerated values in any combination you require. In Java programming, you can combine these values using the ...