Java Reference
In-Depth Information
Message dialog type
Icon
Description
Indicates an error.
ERROR_MESSAGE
Indicates an informational message.
INFORMATION_MESSAGE
WARNING_MESSAGE
Warns of a potential problem.
Poses a question. This dialog normally requires a
response, such as clicking a
Yes
or a
No
button.
QUESTION_MESSAGE
PLAIN_MESSAGE
no
icon
A dialog that contains a message, but no icon.
Fig. 12.3
|
JOptionPane
static
constants for message dialogs.
Though it's possible to perform input and output using the
JOptionPane
dialogs, most
GUI applications require more elaborate user interfaces. The remainder of this chapter
discusses many GUI components that enable application developers to create robust
GUIs. Figure 12.4 lists several basic Swing GUI components that we discuss.
Component
Description
JLabel
Displays
uneditable text
and/or icons.
JTextField
Typically
receives input
from the user.
JButton
Triggers an event when clicked with the mouse.
JCheckBox
Specifies an option that can be
selected
or
not selected
.
JComboBox
A
drop-down list of items
from which the
user
can make a
selection
.
JList
A
list of items
from which the user can make a
selection
by
clicking
on
any
one
of them.
Multiple
elements
can
be selected.
JPanel
An area in which
components
can be
placed
and
organized
.
Fig. 12.4
|
Some basic Swing GUI components.
Swing vs. AWT
There are actually
two
sets of Java GUI components. In Java's early days, GUIs were built
with components from the
Abstract Window Toolkit
(
AWT
) in package
java.awt
.
These look like the native GUI components of the platform on which a Java program ex-
ecutes. For example, a
Button
object displayed in a Java program running on Microsoft
Windows looks like those in other
Windows
applications. On Apple Mac OS X, the
But-
ton
looks like those in other
Mac
applications. Sometimes, even the manner in which a
user can interact with an AWT component
differs between platforms
. The component's ap-
pearance and the way in which the user interacts with it are known as its
look-and-feel
.
