Java Reference
In-Depth Information
25
private final
JRadioButtonMenuItem[] colorItems;
// color menu items
private final
JRadioButtonMenuItem[] fonts;
// font menu items
private final
JCheckBoxMenuItem[] styleItems;
// font style menu items
26
27
28
private final
JLabel displayJLabel;
// displays sample text
29
private final
ButtonGroup fontButtonGroup;
// manages font menu items
30
private final
ButtonGroup colorButtonGroup;
// manages color menu items
31
private
int
style;
// used to create style for font
32
33
// no-argument constructor set up GUI
34
public
MenuFrame()
35
{
36
super
(
"Using JMenus"
);
37
38
JMenu fileMenu =
new
JMenu(
"File"
);
// create file menu
fileMenu.setMnemonic(
'F'
);
// set mnemonic to F
39
40
41
// create About... menu item
42
JMenuItem aboutItem =
new
JMenuItem(
"About..."
);
aboutItem.setMnemonic(
'A'
);
// set mnemonic to A
fileMenu.add(aboutItem);
// add about item to file menu
43
44
45
aboutItem.addActionListener(
46
new
ActionListener()
// anonymous inner class
47
{
48
// display message dialog when user selects About...
49
@Override
50
public
void
actionPerformed(ActionEvent event)
51
{
52
JOptionPane.showMessageDialog(MenuFrame.
this
,
53
"This is an example\nof using menus"
,
54
"About"
,
JOptionPane.PLAIN_MESSAGE
);
55
}
56
}
57
);
58
59
JMenuItem exitItem =
new
JMenuItem(
"Exit"
);
// create exit item
exitItem.setMnemonic(
'x')
;
// set mnemonic to x
fileMenu.add(exitItem);
// add exit item to file menu
60
61
62
exitItem.addActionListener(
63
new
ActionListener()
// anonymous inner class
64
{
65
// terminate application when user clicks exitItem
66
@Override
67
public
void
actionPerformed(ActionEvent event)
68
{
69
System.exit(
0
);
// exit application
70
}
71
}
72
);
73
74
JMenuBar bar =
new
JMenuBar();
// create menu bar
setJMenuBar(bar);
// add menu bar to application
bar.add(fileMenu);
// add file menu to menu bar
75
76
77
Fig. 22.5
|
JMenus
and mnemonics. (Part 2 of 5.)
