Pop-Ups and Choosers - The Definitive Guide to Java Swing - page 275

Table 9-3. JOptionPane Properties

Property Name Data Type Access

accessibleContext AccessibleContext Read-only

icon Icon Read-write bound

initialSelectionValue Object Read-write bound

initialValue Object Read-write bound

inputValue Object Read-write bound

maxCharactersPerLineCount int

Read-only

message Object Read-write bound

messageType int Read-write bound

options Object[]

Read-write bound

optionType int Read-write bound

selectionValues Object[] Read-write bound

UI OptionPaneUI Read-write bound

UIClassID String Read-only

value Object Read-write bound

wantsInput boolean Read-write bound

The wantsInput property is automatically set to true for the input dialog boxes or when the
selectionValues property is non- null . The inputValue property is the item picked from an
input dialog box. The value property indicates the option selected from the button area.

Displaying Multiline Messages
The maxCharactersPerLineCount property is set to an extremely large value, Integer.MAX_VALUE ,
by default. For some strange reason, the Swing developers chose not to provide a setter method
for this property. If you want to change the setting, you must subclass JOptionPane and override the
public int getMaxCharactersPerLineCount() method. This causes a long text message to be
broken up into multiple lines within an option pane. In addition, you cannot use any of the
factory methods because they don't know about your subclass.
To help you create narrow JOptionPane components, you can add the source shown in
Listing 9-2 to the OptionPaneUtils class definition shown earlier in Listing 9-1. The new method
provides a way of specifying the desired option pane character width.