Java Swing, 2nd Edition

Getting the Results

Now that we’ve seen how to create all sorts of useful dialog boxes, it’s time to take a look at how to retrieve information about the user’s interaction with the dialog. Table 10-7 showed the return types of the various methods. Here’s a quick summary of what the returned values mean.

Input Dialogs

The versions that do not take an array of selection values return a String. This is the data entered by the user. The methods that do take an array of selection values return an Object reflecting the selected option. It’s up to the L&F to determine the component used for presenting the options. Typically, a JComboBox is used if there are fewer than 20 choices, and a JList is used if there are 20 or more.^[14] In any case, if the user presses the Cancel button, null is returned.

Confirm Dialogs

These methods return an int reflecting the button pressed by the user. The possible values are: YES_OPTION, NO_OPTION, CANCEL_OPTION, and OK_OPTION. CLOSED_OPTION is returned if the user closes the window without selecting anything.

Message Dialogs

These methods have void return types because they do not request a user response.

Option Dialogs

If no options are specified, this method returns one of the constant values YES_OPTION, NO_OPTION, CANCEL_OPTION, and OK_OPTION. If options are explicitly defined, the return value gives the index to the array of options that matches the button selected by the user. CLOSED_OPTION is returned if the user closes the window without selecting anything. ...