Module java.desktop
Package javax.swing

Class JOptionPane

java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.JOptionPane
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible
@JavaBean(defaultProperty="UI", description="A component which implements standard dialog box controls.") public class JOptionPane extends JComponent implements Accessible
JOptionPane makes it easy to pop up a standard dialog box that prompts users for a value or informs them of something. For information about using JOptionPane, see How to Make Dialogs, a section in The Java Tutorial.

While the JOptionPane class may appear complex because of the large number of methods, almost all uses of this class are one-line calls to one of the static showXxxDialog methods shown below:

Common JOptionPane method names and their descriptions
Method Name Description
showConfirmDialog Asks a confirming question, like yes/no/cancel.
showInputDialog Prompt for some input.
showMessageDialog Tell the user about something that has happened.
showOptionDialog The Grand Unification of the above three.
Each of these methods also comes in a showInternalXXX flavor, which uses an internal frame to hold the dialog box (see JInternalFrame). Multiple convenience methods have also been defined -- overloaded versions of the basic methods that use different parameter lists.

All dialogs are modal. Each showXxxDialog method blocks the caller until the user's interaction is complete.

Common dialog
icon message
input value
option buttons
The basic appearance of one of these dialog boxes is generally similar to the picture above, although the various look-and-feels are ultimately responsible for the final result. In particular, the look-and-feels will adjust the layout to accommodate the option pane's ComponentOrientation property.

Parameters:
The parameters to these methods follow consistent patterns:

parentComponent
Defines the Component that is to be the parent of this dialog box. It is used in two ways: the Frame that contains it is used as the Frame parent for the dialog box, and its screen coordinates are used in the placement of the dialog box. In general, the dialog box is placed just below the component. This parameter may be null, in which case a default Frame is used as the parent, and the dialog will be centered on the screen (depending on the L&F).
message
A descriptive message to be placed in the dialog box. In the most common usage, message is just a String or String constant. However, the type of this parameter is actually Object. Its interpretation depends on its type:
Object[]
An array of objects is interpreted as a series of messages (one per object) arranged in a vertical stack. The interpretation is recursive -- each object in the array is interpreted according to its type.
Component
The Component is displayed in the dialog.
Icon
The Icon is wrapped in a JLabel and displayed in the dialog.
others
The object is converted to a String by calling its toString method. The result is wrapped in a JLabel and displayed.
messageType
Defines the style of the message. The Look and Feel manager may lay out the dialog differently depending on this value, and will often provide a default icon. The possible values are:
  • ERROR_MESSAGE
  • INFORMATION_MESSAGE
  • WARNING_MESSAGE
  • QUESTION_MESSAGE
  • PLAIN_MESSAGE
optionType
Defines the set of option buttons that appear at the bottom of the dialog box:
  • DEFAULT_OPTION
  • YES_NO_OPTION
  • YES_NO_CANCEL_OPTION
  • OK_CANCEL_OPTION
You aren't limited to this set of option buttons. You can provide any buttons you want using the options parameter.
options
A more detailed description of the set of option buttons that will appear at the bottom of the dialog box. The usual value for the options parameter is an array of Strings. But the parameter type is an array of Objects. A button is created for each object depending on its type:
Component
The component is added to the button row directly.
Icon
A JButton is created with this as its label.
other
The Object is converted to a string using its toString method and the result is used to label a JButton.
icon
A decorative icon to be placed in the dialog box. A default value for this is determined by the messageType parameter.
title
The title for the dialog box.
initialValue
The default selection (input value).

When the selection is changed, setValue is invoked, which generates a PropertyChangeEvent.

If a JOptionPane has configured to all input setWantsInput the bound property JOptionPane.INPUT_VALUE_PROPERTY can also be listened to, to determine when the user has input or selected a value.

When one of the showXxxDialog methods returns an integer, the possible values are:

  • YES_OPTION
  • NO_OPTION
  • CANCEL_OPTION
  • OK_OPTION
  • CLOSED_OPTION
Examples:
Show an error dialog that displays the message, 'alert':
JOptionPane.showMessageDialog(null, "alert", "alert", JOptionPane.ERROR_MESSAGE);
Show an internal information dialog with the message, 'information': 
 JOptionPane.showInternalMessageDialog(frame, "information",
             "information", JOptionPane.INFORMATION_MESSAGE);
Show an information panel with the options yes/no and message 'choose one': 
JOptionPane.showConfirmDialog(null,
             "choose one", "choose one", JOptionPane.YES_NO_OPTION);
Show an internal information dialog with the options yes/no/cancel and message 'please choose one' and title information: 
JOptionPane.showInternalConfirmDialog(frame,
             "please choose one", "information",
             JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.INFORMATION_MESSAGE);
Show a warning dialog with the options OK, CANCEL, title 'Warning', and message 'Click OK to continue': 
 Object[] options = { "OK", "CANCEL" };
 JOptionPane.showOptionDialog(null, "Click OK to continue", "Warning",
             JOptionPane.DEFAULT_OPTION, JOptionPane.WARNING_MESSAGE,
             null, options, options[0]);
Show a dialog asking the user to type in a String:
String inputValue = JOptionPane.showInputDialog("Please input a value");
Show a dialog asking the user to select a String: 
 Object[] possibleValues = { "First", "Second", "Third" };

 Object selectedValue = JOptionPane.showInputDialog(null,
             "Choose one", "Input",
             JOptionPane.INFORMATION_MESSAGE, null,
             possibleValues, possibleValues[0]);
Direct Use:
To create and use an JOptionPane directly, the standard pattern is roughly as follows: 
     JOptionPane pane = new JOptionPane(arguments);
     pane.set.Xxxx(...); // Configure
     JDialog dialog = pane.createDialog(parentComponent, title);
     dialog.setVisible(true);
     Object selectedValue = pane.getValue();
     if(selectedValue == null)
       return CLOSED_OPTION;
     //If there is not an array of option buttons:
     if(options == null) {
       if(selectedValue instanceof Integer)
          return ((Integer)selectedValue).intValue();
       return CLOSED_OPTION;
     }
     //If there is an array of option buttons:
     for(int counter = 0, maxCounter = options.length;
        counter < maxCounter; counter++) {
        if(options[counter].equals(selectedValue))
        return counter;
     }
     return CLOSED_OPTION;

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Since:
1.2
See Also: