Option dialogs -- JOptionPane

Across many applications we will want have dialogs that convey a certain message.

We may want to

• Warn the user -- Warning Dialog
• Report an error -- Error Dialog
• Ask a simple question (Yes/No query) -- Question Dialog
• Simply Inform the user -- Information Dialog
• There is also a plain message form -- Message Dialog

The JOptionPane dialog offers a is fairly consistent (look-and-feel dependent) set of functional dialogs

Each dialog possess up to 4 components:

icon area

-- displays an icon.

button area

-- populated with one or more buttons (Yes, No, OK, Cancel, and so on) according to an option type specified by the developer

message area

-- shows a simple text string as a message.

input area

-- content is controlled by the setWantsInput() method allowing the presence of a data entry field that requires the user to enter some text.

There are four dialog types which can be further enhanced by by a messageType parameter in the show...Dialog() methods.

They each have different functionality and should be used in the most applicable fashion only. They are characterised by a slightly different appearance -- buttons available, input possible etc.

The four dialog types are:

Message Dialog

-- displays information to the user, includes a single OK button

Error Message Dialog

Confirm Dialog

-- Asks the user to confirm some information, includes buttons such as Yes and No, or OK and Cancel.

Information Confirm Dialog

Question Confirm Dialog

Plain Message Confirm Dialog

Input Dialog

-- Provides some way (JTextField,JComboBox, JList) for entry of data, always includes an OK and Cancel button.

Warning Input Dialog

Option Dialog

-- general programmer defined dialog, can contain any set of buttons

Note that are several permutation of the predefined style of dialogs:

• The dialog types define the overall style of the dialog
• The messageType parameter defines what buttons are labelled and also the default icon displayed for the appropriate messageType (see the above figures)

The messageType and other dialog properties are controlled by JOptionPane constants.