ADVANCED GUIS AND GRAPHICS - Java Programming: From Problem Analysis to Program Design - page 820

//register the item listener to the check boxes
boldCB.addItemListener( this );
italicCB.addItemListener( this );

//add the check boxes to the pane
c.add(boldCB);
c.add(italicCB);

}

To specify the font and style of the text, we use two int variables: intBold and
intItalic . These variables are set to Font.PLAIN when the check boxes are not
checked. They are set to Font.BOLD and Font.ITALIC , respectively, if the correspond-
ing check boxes are checked. To create bold and italic fonts, you simply add the values of
the variables bold and italic . In other words, you can create desired fonts by just using
intBold + intItalic as the style value. Note that because Font.PLAIN has a value of
zero, Font.PLAIN + Font.PLAIN remains Font.PLAIN . The paint method can be used
to set the color and font, and to display the welcome message. The definition of the
method paint can be written as follows:

public void paint(Graphics g)
{

super .paint(g);
g.setColor(Color.red);
g.setFont( new Font("Courier", intBold + intItalic, 24));
g.drawString("Welcome to Java Programming", 30, 30);

}

To make the program respond to the events generated by the check boxes, next we write
the definition of the method itemStateChanged . As shown earlier, the method
itemStateChanged has one parameter, e ,ofthetype ItemEvent . Because there are
two check boxes, we use the method getSource to identify the box generating the event.
The expression:
e.getSource() == boldCB
is true if the check box associated with boldCB generated the event. Similarly, the
expression:
e.getSource() == italicCB
is true if the check box associated with italicCB generated the event.
After identifying the check box that generated the event, we determine whether the user
selected or deselected the check box. For this, we use the method getStateChange of
the class ItemEvent that returns either the constant ItemEvent.SELECTED or the
constant ItemEvent.DESELECTED , which are defined in the class ItemEvent . For
example, the expression:
e.getStateChange() == ItemEvent.SELECTED
is true if the event e corresponds to selecting the check box.