INTRODUCTION TO OBJECTS AND INPUT/OUTPUT - Java Programming: From Problem Analysis to Program Design - page 141

The method showMessageDialog has four parameters, which are described in Table 3-3.

TABLE 3-3 Parameters for the Method showMessageDialog

Parameter Description

parentComponent

This is an object that represents the parent of the
dialog box. For now, we will specify the
parentComponent to be null , in which case
the program uses a default component that causes
the dialog box to appear in the middle of the
screen. Note that null is a reserved word in Java.

3

messageStringExpression

The messageStringExpression is
evaluated and its value appears in the dialog box.

boxTitleString The boxTitleString represents the title of

the dialog box.

messageType

An int value representing the type of icon that will
appear in the dialog box. Alternatively, you can use
certain JOptionPane options described below.

Table 3-4 describes the options of the class JOptionPane that can be used with the
parameter messageType . The option name is shown in bold. Examples 3-9 through 3-11
illustrate these options.

TABLE 3-4 JOptionPane Options for the Parameter messageType

messageType Description

The error icon, , is displayed in

JOptionPane.ERROR_MESSAGE

the dialog box.

The information icon, ,is

JOptionPane.INFORMATION_MESSAGE

displayed in the dialog box.

JOptionPane.PLAIN_MESSAGE

No icon appears in the dialog box.

The question icon, , is displayed

JOptionPane.QUESTION_MESSAGE

in the dialog box.

The warning icon, , is displayed

JOptionPane.WARNING_MESSAGE

in the dialog box.