Layout Management and GUI Components - Learning Java Through Games - page 284

FIGURE 12.7: Example of a dialog box.

12.11 Creating Dialog Boxes
A dialog box is similar to a window (i.e., a JFrame ). However, it cannot be minimized
or restored. It has a single close button in the top right-hand corner of the window. For
example, when you create a game, you may want to add an About dialog box; see Figure 12.7.
This can include your name, when the game was developed, copyright considerations, and
so on. A dialog box has a key property that distinguishes it from a regular window. It can
be either modal or modeless .

A modal dialog box prevents interaction with all other windows of the application.
A modeless dialog box allows us to interact with it and other windows of the application
at the same time.

A dialog box is created by creating an object of type JDialog . The constructor takes
as input a reference to the parent window, the title of the dialog box, and a Boolean value.
If the Boolean value is true , then the dialog is modal. Otherwise, the dialog is modeless.
Note that a reference to the parent window is needed in order to disable interaction with
the parent window when the dialog box is modal.
Below is a simple example of how to create an about dialog window. The AboutFrame
class creates a menu bar that has a single menu and a single menu item. When the menu
item is selected, an about dialog box is created and displayed.

import java .awt. event . ∗ ;
import javax . swing . ∗ ;

public class AboutProgram {

public static void main(String [] args)

{

AboutFrame f = new AboutFrame () ;