Extending the GUI - Beginning Java - page 1079

// Set up the size choice using a spinner as before...

// Set up style options using radio buttons
bold = new JRadioButton("Bold", (font.getStyle() & Font.BOLD) > 0);
italic = new JRadioButton("Italic", (font.getStyle() & Font.ITALIC) > 0);
bold.addItemListener(new StyleListener(Font.BOLD)); // Add button listeners
italic.addItemListener(new StyleListener(Font.ITALIC));
JPanel stylePane = new JPanel(true); // Create style pane

stylePane.add(bold); // Add buttons

stylePane.add(italic); // to style pane...

gbLayout.setConstraints(stylePane, constraints); // Set pane constraints

dataPane.add(stylePane); // Add the pane

getContentPane().add(dataPane, BorderLayout.CENTER);
pack();
setVisible(false);

}

Directory "Sketcher 5 displaying a font dialog"

It looks like a lot of code, but it's repetitive, as you have two radio buttons. The second argument to the
JRadioButton constructor sets the state of the button. If the existing style of the current font is BOLD and/
or ITALIC , the initial states of the buttons are set accordingly. You add a listener of type StyleListener
for each button, and you add a definition for StyleListener as an inner class to FontDialog in a moment.
Note that you pass the style constant that corresponds to the set state of the button to the constructor for the
listener.
The stylePane object presents the buttons using the default FlowLayout manager, and this pane is added
as the last row to dataPane . The final step is to add the dataPane object as the central pane in the content
pane for the dialog. The call to pack() lays out the dialog components with their preferred sizes if possible,
and the setVisible() call with the argument false means that the dialog is initially hidden. Because this is
a complex dialog, you don't want to create a new object each time you want to display the font dialog. You
just call the setVisible() method for the dialog object with the argument true when you want to display
it.

Listening for Radio Buttons
The inner class, StyleListener , in the FontDialog class works on principles that you have seen before.
A radio button (or a checkbox) generates events of type java.awt.ItemEvent , and the listener class must
implement the java.awt.ItemListener interface:

class StyleListener implements ItemListener {
public StyleListener(int style) {
this.style = style;

}

public void itemStateChanged(ItemEvent e) {