Java Swing, 2nd Edition

The JWindow Class

JWindow is an extension of java.awt.Window that uses a JRootPane as its single component. Other than this core distinction, JWindow does not change anything defined by the Window class.

In AWT, one common reason for using the Window class was to create a pop-up menu. Since Swing explicitly provides a JPopupMenu class (see Chapter 14), there is no need to extend JWindow for this purpose. The only time you’ll use JWindow is if you have something that needs to be displayed in its own window without the adornments added by JFrame. Remember, this means that the window can only be moved or closed programmatically (or via the user’s platform-specific window manager controls, if available).

One possible use for JWindow would be to display a splash screen when an application is starting up. Many programs display screens like this, containing copyright information, resource loading status, etc. Here’s such a program:

// SplashScreen.java // import java.awt.*; import javax.swing.*; public class SplashScreen extends JWindow { private int duration; public SplashScreen(int d) { duration = d; } // A simple little method to show a title screen in the center of the screen for // the amount of time given in the constructor public void showSplash( ) { JPanel content = (JPanel)getContentPane( ); content.setBackground(Color.white); // Set the window's bounds, centering the window. int width = 450; int height =115; Dimension screen = Toolkit.getDefaultToolkit( ).getScreenSize( ); int ...