SWT: A Developer's Notebook

Chapter 10. SWT Composites and Groups

Until now, all examples that have been created have included widgets that were added directly to an instance of Shell. This approach works well for simple interfaces, but more complex designs require the use of a different layout manager for different parts of the window. For example, you might want a row of buttons at the bottom of a window—a perfect situation for RowLayout—while data is displayed above the buttons in the form of a grid, a perfect situation for GridLayout.

The SWT provides for these situations with two additional classes that can act as containers for widgets: Composite and Group. These classes are located in the org.eclipse.swt.widgets package.

Before you learn how to use the Composite and Group classes together with layouts to build complex user interfaces for use in your applications, you should first gain a basic understanding of the Composite and Group classes themselves. Since Group is a subclass of Composite, it makes sense to begin this discussion by covering the Composite class.

Composite objects are created simply to contain other widgets. Composite is an ancestor of every SWT class to which you can add widgets, including Shell . For that reason, you can think of a Composite as being simply the working area of a Shell, without the styles associated with the aspects of Shell that make windows—the titlebar, control menu, etc.

Subclassing the Composite Class

One major difference between the Composite and Shell classes ...