Package javafx.scene.input

Class KeyEvent

java.lang.Object
java.util.EventObject
javafx.event.Event
javafx.scene.input.InputEvent
javafx.scene.input.KeyEvent
All Implemented Interfaces:
Serializable, Cloneable
public final class KeyEvent extends InputEvent
An event which indicates that a keystroke occurred in a Node.

This event is generated when a key is pressed, released, or typed. Depending on the type of the event it is passed to onKeyPressed, onKeyTyped or onKeyReleased function.

"Key typed" events are higher-level and generally do not depend on the platform or keyboard layout. They are generated when a Unicode character is entered, and are the preferred way to find out about character input. In the simplest case, a key typed event is produced by a single key press (e.g., 'a'). Often, however, characters are produced by series of key presses (e.g., SHIFT + 'a'), and the mapping from key pressed events to key typed events may be many-to-one or many-to-many. Key releases are not usually necessary to generate a key typed event, but there are some cases where the key typed event is not generated until a key is released (e.g., entering ASCII sequences via the Alt-Numpad method in Windows). No key typed events are generated for keys that don't generate Unicode characters (e.g., action keys, modifier keys, etc.).

The character variable always contains a valid Unicode character(s) or CHAR_UNDEFINED. Character input is reported by key typed events; key pressed and key released events are not necessarily associated with character input. Therefore, the character variable is guaranteed to be meaningful only for key typed events.

For key pressed and key released events, the code variable contains the event's key code. For key typed events, the code variable always contains KeyCode.UNDEFINED.

"Key pressed" and "key released" events are lower-level and depend on the platform and keyboard layout. They are generated whenever a key is pressed or released, and are the only way to find out about keys that don't generate character input (e.g., action keys, modifier keys, etc.). The key being pressed or released is indicated by the code variable, which contains a virtual key code.

For triggering context menus see the ContextMenuEvent.

Since:
JavaFX 2.0
See Also:

  • Field Details

    • ANY

      public static final EventType<KeyEvent> ANY
      Common supertype for all key event types.

    • KEY_PRESSED

      public static final EventType<KeyEvent> KEY_PRESSED
      This event occurs when a key has been pressed.

    • KEY_RELEASED

      public static final EventType<KeyEvent> KEY_RELEASED
      This event occurs when a key has been released.

    • KEY_TYPED

      public static final EventType<KeyEvent> KEY_TYPED
      This event occurs when a character-generating key was typed (pressed and released). The event contains the character field containing the typed string, the code and text fields are not used.

    • CHAR_UNDEFINED

      public static final String CHAR_UNDEFINED
      KEY_PRESSED and KEY_RELEASED events which do not map to a valid Unicode character use this for the keyChar value.

  • Constructor Details

    • KeyEvent

      public KeyEvent(Object source, EventTarget target, EventType<KeyEvent> eventType, String character, String text, KeyCode code, boolean shiftDown, boolean controlDown, boolean altDown, boolean metaDown)
      Constructs new KeyEvent event with null source and target and KeyCode object directly specified.
      Parameters:
      source - the source of the event. Can be null.
      target - the target of the event. Can be null.
      eventType - The type of the event.
      character - The character or sequence of characters associated with the event
      text - A String describing the key code
      code - The integer key code
      shiftDown - true if shift modifier was pressed.
      controlDown - true if control modifier was pressed.
      altDown - true if alt modifier was pressed.
      metaDown - true if meta modifier was pressed.
      Since:
      JavaFX 8.0

    • KeyEvent

      public KeyEvent(EventType<KeyEvent> eventType, String character, String text, KeyCode code, boolean shiftDown, boolean controlDown, boolean altDown, boolean metaDown)
      Constructs new KeyEvent event with null source and target and KeyCode object directly specified.
      Parameters:
      eventType - The type of the event.
      character - The character or sequence of characters associated with the event
      text - A String describing the key code
      code - The integer key code
      shiftDown - true if shift modifier was pressed.
      controlDown - true if control modifier was pressed.
      altDown - true if alt modifier was pressed.
      metaDown - true if meta modifier was pressed.
      Since:
      JavaFX 8.0

  • Method Details

    • getCharacter

      public final String getCharacter()
      The Unicode character or sequence of characters associated with the key typed event. Contains multiple elements if the key produced a single Unicode character from outside of the Basic Multilingual Plane which needs to be encoded by the corresponding surrogate pair in Java or if the key produced multiple Unicode characters itself.

      For example, character will have the value "A" for a key typed event generated by pressing SHIFT + 'a'. For key pressed and key released events, character is always CHAR_UNDEFINED.

      Returns:
      The Unicode character(s) associated with the key typed event

    • getText

      public final String getText()
      A String describing the key code, such as "HOME", "F1" or "A", for key pressed and key released events. For key typed events, text is always the empty string.
      Returns:
      A String describing the key code

    • getCode

      public final KeyCode getCode()
      The key code associated with the key in this key pressed or key released event. For key typed events, code is always KeyCode.UNDEFINED.
      Returns:
      The key code associated with the key in this event, KeyCode.UNDEFINED for key typed event

    • isShiftDown

      public final boolean isShiftDown()
      Returns whether or not the Shift modifier is down on this event.
      Returns:
      whether or not the Shift modifier is down on this event.

    • isControlDown

      public final boolean isControlDown()
      Returns whether or not the Control modifier is down on this event.
      Returns:
      whether or not the Control modifier is down on this event.

    • isAltDown

      public final boolean isAltDown()
      Returns whether or not the Alt modifier is down on this event.
      Returns:
      whether or not the Alt modifier is down on this event.

    • isMetaDown

      public final boolean isMetaDown()
      Returns whether or not the Meta modifier is down on this event.
      Returns:
      whether or not the Meta modifier is down on this event.

    • toString

      public String toString()
      Returns a string representation of this KeyEvent object.
      Overrides:
      toString in class EventObject
      Returns:
      a string representation of this KeyEvent object.

    • copyFor

      public KeyEvent copyFor(Object newSource, EventTarget newTarget)
      Description copied from class: Event
      Creates and returns a copy of this event with the specified event source and target. If the source or target is set to null, it is replaced by the NULL_SOURCE_TARGET value.
      Overrides:
      copyFor in class Event
      Parameters:
      newSource - the new source of the copied event
      newTarget - the new target of the copied event
      Returns:
      the event copy with the new source and target

    • copyFor

      public KeyEvent copyFor(Object source, EventTarget target, EventType<KeyEvent> type)
      Creates a copy of the given event with the given fields substituted.
      Parameters:
      source - the new source of the copied event
      target - the new target of the copied event
      type - the new event type.
      Returns:
      the event copy with the fields substituted
      Since:
      JavaFX 8.0

    • duplicate

      public Event duplicate()
      Description copied from class: Event
      Creates and returns a copy of this Event.
      Overrides:
      duplicate in class Event
      Returns:
      a new instance of Event with all values copied from this Event.

    • getEventType

      public EventType<KeyEvent> getEventType()
      Description copied from class: Event
      Gets the event type of this event. Objects of the same Event class can have different event types. These event types further specify what kind of event occurred.
      Overrides:
      getEventType in class InputEvent
      Returns:
      the event type