Java Reference
In-Depth Information
As another example, the right dialog window in Fig. 17.8 was created with
fourth argument
JOptionPane.INFORMATION_MESSAGE
.
Modal windows
These dialog windows are
modal
dialog windows. This means that, when
they are shown, they capture the focus, and clicking on other windows belong-
ing to this execution will have no effect. You must close this window before any-
thing else can happen in the program.
The first argument, the parent
The first argument in calls to
showMessageDialog
is called the
parent win-
dow
of the dialog window. If the first argument is
null
, the dialog window
appears in the center of the monitor. However, suppose the first argument is the
name
window
(say) of some window that is already showing on the monitor.
Then, when the dialog window is created and shown, it is shown in front of win-
dow
window
.
Function showInputDialog
String
function
JOptionPane.showInputDialog
displays a modal dialog
window with a message and returns text typed by the user. An example window
appears to the left in Fig. 17.19. A call has four parameters:
Activity
17-5.2
1. The
parent
(as with method
showMessageDialog
).
2. The message (a
String
). In the example, it is
"What's your opinion
about eating meat?"
.
3. The title (a
String
). In the example, it is:
"question message"
.
4. The style of the window, which tells what picture to put in the window. It
is one of the following constants of
JOptionPane
:
JOptionPane.ERROR_MESSAGE
JOptionPane.INFORMATION_MESSAGE
JOptionPane.WARNING_MESSAGE
JOptionPane.QUESTION_MESSAGE
JOptionPane.PLAIN_MESSAGE
Figure 17.20:
A
showOptionDialog
window
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