Swing I - Absolute Java - page 1007

• A panel is a container object that is used to group components inside of a larger
container. Panels are objects in the class JPanel .
• A menu item is a choice on a menu. A menu item is realized in your code as an object
of the class JMenuItem . A menu is an object of the class JMenu . A menu item is added
to a JMenu with the method add . A menu bar is an object of the class JMenuBar . A
menu is added to a JMenuBar with the method add .
• A JMenuBar can be added to a JFrame with the method setJMenuBar . It can also be
added using the method add , just as any other component can be added.
• Both buttons and menu items fire action events and so normally have one or more
action listeners registered with them to respond to the events.
Answers to Self-Test Exercises
1. The JFrame class.
2. Sizes in Swing are measured in pixels.
3. someWindow.setDefaultCloseOperation(
JFrame.DO_NOTHING_ON_CLOSE);
4. someWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
5. When you click the minimizing button, the JFrame is reduced to an icon, usually
at the bottom of your monitor screen.
6 . someWindow.setVisible(n > 0);
The following also works but is not good style:
if (n > 0)
someWindow.setVisible( true );
else
someWindow.setVisible( false );
7. An action event.
8. public void actionPerformed(ActionEvent e)
9. Change
JFrame firstWindow = new JFrame();
to
JFrame firstWindow = new JFrame("My First Window");
Alternatively, you can add the following:
firstWindow.setTitle("My First Window");