Action, Key, and Item Events

Flashcards focused on Java Swing Action, Key, and Item Events, including corresponding event classes, listener methods, and GUI components.

ActionEvent Class

An event class generated when a button is clicked or an item of a list is double-clicked.

actionPerformed(ActionEvent e)

An ActionListener method invoked when an action occurs.

KeyEvent Class

An event class indicating a keystroke occurred, passed to registered KeyListener or KeyAdapter objects as a low-level event by a Swing component.

keyTyped(KeyEvent evt)

A KeyListener method generated when a Unicode character is entered, which does not depend on platform or keyboard layout.

ASCII

Character set represented by $2^8$ combinations.

UNICODE

Character set represented by $2^{16}$ combinations.

getKeyChar()

A method that returns a valid Unicode character reported by KEY_TYPED events.

getKeyCode()

A method that returns the event's keycode based on a specific keyboard layout for KEY_PRESSED and KEY_RELEASED events, returning VK_Undefined for key typed events.

getExtendedKeyCode()

A method used with many international keyboard layouts such as the smiley emoticon key.

Virtual key codes

Codes that report which keyboard key has been pressed rather than a specific character.

JCheckBox Class

A Swing component representing an item that can be selected or deselected to turn an option on or off.

JRadioButton Class

A Swing component used to let the user select one of a set of mutually exclusive options.

ButtonGroup

A helper class that groups radio buttons and manages the group's state so only one button in the group can be selected at a time.

JComboBox Class

A Swing component that combines a button or editable field and a drop-down list.

ItemEvent Class

An event passed to the ItemListener whenever the selected item in a list control (such as a list box or combo box) is changed.

getItem()

An ItemListener event handler method that returns the item that was selected or deselected.

getSource()

An ItemListener event handler method that returns the object on which the event occurred.

getStateChanged()

An ItemListener event handler method that returns either SELECTED or DESELECTED to indicate the state change.