Java Reference
In-Depth Information
If the message is an array of objects (
Object[ ]
), make the
JOptionPane
place each entry
onto a separate row.
•
If the message is a
Component
, place the component in the message area.
•
•
If the message is an
Icon
, place the
Icon
within a
JLabel
and display the label in the
message area.
If the message is an
Object
, convert it to a
String
with
toString()
, place the
String
in a
JLabel
, and display the label in the message area.
•
The JOptionPane Message Type and Icon Arguments
The
messageType
constructor argument is used to represent the type of message being displayed
within the
JOptionPane
. If you don't provide a custom icon for the
JOptionPane
, the installed
look and feel will use the
messageType
argument setting to determine which icon to display
within the icon area. Five different message types are available as
JOptionPane
constants:
•
ERROR_MESSAGE
for displaying an error message
•
INFORMATION_MESSAGE
for displaying an informational message
•
QUESTION_MESSAGE
for displaying a query message
•
WARNING_MESSAGE
for displaying a warning message
•
PLAIN_MESSAGE
for displaying any other type of message
If you're using a constructor with both
messageType
and
icon
arguments and want the
JOptionPane
to use the default icon for the
messageType
, just specify
null
as the value for the
icon
argument. If the
icon
argument is non-
null
, the specified icon will be used, no matter
what the message type is.
If the
messageType
constructor argument isn't specified, the default message type is
PLAIN_MESSAGE
.
The JOptionPane Option Type Argument
The
optionType
constructor argument is used to determine the configuration for the set of
buttons in the button area. If one of the
options
argument described next is provided, then the
optionType
argument is ignored and configuration for the set of buttons is acquired from the
options
argument. Four different option types are available as
JOptionPane
constants:
•
DEFAULT_OPTION
for a single OK button
•
OK_CANCEL_OPTION
for OK and Cancel buttons
•
YES_NO_CANCEL_OPTION
for Yes, No, and Cancel buttons
•
YES_NO_OPTION
for Yes and No buttons
If the
optionType
constructor argument isn't specified, the default option type is
DEFAULT_OPTION
.
