java.awt.event

Class MouseEvent

java.lang.Object

java.util.EventObject

java.awt.AWTEvent

java.awt.event.ComponentEvent

java.awt.event.InputEvent

java.awt.event.MouseEvent

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

MouseWheelEvent

public class MouseEvent
extends InputEvent

An event which indicates that a mouse action occurred in a component. A mouse action is considered to occur in a particular component if and only if the mouse cursor is over the unobscured part of the component's bounds when the action happens. Component bounds can be obscurred by the visible component's children or by a menu or by a top-level window. This event is used both for mouse events (click, enter, exit) and mouse motion events (moves and drags).

This low-level event is generated by a component object for:

• Mouse Events
  • a mouse button is pressed
  • a mouse button is released
  • a mouse button is clicked (pressed and released)
  • the mouse cursor enters the unobscured part of component's geometry
  • the mouse cursor exits the unobscured part of component's geometry
• Mouse Motion Events
  • the mouse is moved
  • the mouse is dragged

A MouseEvent object is passed to every MouseListener or MouseAdapter object which is registered to receive the "interesting" mouse events using the component's addMouseListener method. (MouseAdapter objects implement the MouseListener interface.) Each such listener object gets a MouseEvent containing the mouse event.

A MouseEvent object is also passed to every MouseMotionListener or MouseMotionAdapter object which is registered to receive mouse motion events using the component's addMouseMotionListener method. (MouseMotionAdapter objects implement the MouseMotionListener interface.) Each such listener object gets a MouseEvent containing the mouse motion event.

When a mouse button is clicked, events are generated and sent to the registered MouseListeners. The state of modal keys can be retrieved using InputEvent.getModifiers() and InputEvent.getModifiersEx(). The button mask returned by InputEvent.getModifiers() reflects only the button that changed state, not the current state of all buttons. (Note: Due to overlap in the values of ALT_MASK/BUTTON2_MASK and META_MASK/BUTTON3_MASK, this is not always true for mouse events involving modifier keys). To get the state of all buttons and modifier keys, use InputEvent.getModifiersEx(). The button which has changed state is returned by getButton()

For example, if the first mouse button is pressed, events are sent in the following order:

    id              modifiers    button           
    MOUSE_PRESSED:  BUTTON1_MASK BUTTON1
    MOUSE_RELEASED: BUTTON1_MASK BUTTON1
    MOUSE_CLICKED:  BUTTON1_MASK BUTTON1
 

When multiple mouse buttons are pressed, each press, release, and click results in a separate event.

For example, if the user presses button 1 followed by button 2, and then releases them in the same order, the following sequence of events is generated:

    id              modifiers    button           
    MOUSE_PRESSED:  BUTTON1_MASK BUTTON1
    MOUSE_PRESSED:  BUTTON2_MASK BUTTON2
    MOUSE_RELEASED: BUTTON1_MASK BUTTON1
    MOUSE_CLICKED:  BUTTON1_MASK BUTTON1
    MOUSE_RELEASED: BUTTON2_MASK BUTTON2
    MOUSE_CLICKED:  BUTTON2_MASK BUTTON2
 

If button 2 is released first, the MOUSE_RELEASED/MOUSE_CLICKED pair for BUTTON2_MASK arrives first, followed by the pair for BUTTON1_MASK.

MOUSE_DRAGGED events are delivered to the Component in which the mouse button was pressed until the mouse button is released (regardless of whether the mouse position is within the bounds of the Component). Due to platform-dependent Drag&Drop implementations, MOUSE_DRAGGED events may not be delivered during a native Drag&Drop operation. In a multi-screen environment mouse drag events are delivered to the Component even if the mouse position is outside the bounds of the GraphicsConfiguration associated with that Component. However, the reported position for mouse drag events in this case may differ from the actual mouse position:

• In a multi-screen environment without a virtual device:
  The reported coordinates for mouse drag events are clipped to fit within the bounds of the GraphicsConfiguration associated with the Component.
• In a multi-screen environment with a virtual device:
  The reported coordinates for mouse drag events are clipped to fit within the bounds of the virtual device associated with the Component.

Restrictions

Implementations of this Profile exhibit certain restrictions with respect to mouse events, specifically:

• An implementation need not support the generation of all mouse events. In such a case, it may partially support the generation of mouse events or not support them at all.

  Regardless of this restriction, applications may still create MouseEvent objects and post them to the system event queue.

For more information, see Profile-specific properties.

Note: These restrictions and their corresponding properties apply only to the MouseEvent class, and not to its subclass, MouseWheelEvent.

Since:

1.1

Author:

Carl Quinn 1.45, 01/23/03

See Also:

MouseAdapter, MouseListener, MouseMotionAdapter, MouseMotionListener, Tutorial: Writing a Mouse Listener, Tutorial: Writing a Mouse Motion Listener, Reference: The Java Class Libraries (update file), Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	BUTTON1 Indicates mouse button #1; used by getButton().
static int	BUTTON2 Indicates mouse button #2; used by getButton().
static int	BUTTON3 Indicates mouse button #3; used by getButton().
static int	MOUSE_CLICKED The "mouse clicked" event.
static int	MOUSE_DRAGGED The "mouse dragged" event.
static int	MOUSE_ENTERED The "mouse entered" event.
static int	MOUSE_EXITED The "mouse exited" event.
static int	MOUSE_FIRST The first number in the range of ids used for mouse events.
static int	MOUSE_LAST The last number in the range of ids used for mouse events.
static int	MOUSE_MOVED The "mouse moved" event.
static int	MOUSE_PRESSED The "mouse pressed" event.
static int	MOUSE_RELEASED The "mouse released" event.
static int	MOUSE_WHEEL The "mouse wheel" event.
static int	NOBUTTON Indicates no mouse buttons; used by getButton().

Fields inherited from class java.awt.event.InputEvent

ALT_DOWN_MASK, ALT_GRAPH_DOWN_MASK, ALT_GRAPH_MASK, ALT_MASK, BUTTON1_DOWN_MASK, BUTTON1_MASK, BUTTON2_DOWN_MASK, BUTTON2_MASK, BUTTON3_DOWN_MASK, BUTTON3_MASK, CTRL_DOWN_MASK, CTRL_MASK, META_DOWN_MASK, META_MASK, SHIFT_DOWN_MASK, SHIFT_MASK

Fields inherited from class java.awt.event.ComponentEvent

COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN

Fields inherited from class java.awt.AWTEvent

ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor and Description
MouseEvent(Component source, int id, long when, int modifiers, int x, int y, int clickCount, boolean popupTrigger) Constructs a MouseEvent object with the specified source component, type, modifiers, coordinates, and click count.
MouseEvent(Component source, int id, long when, int modifiers, int x, int y, int clickCount, boolean popupTrigger, int button) Constructs a MouseEvent object with the specified source component, type, modifiers, coordinates, and click count.

Method Summary

Methods

Modifier and Type	Method and Description
int	getButton() Returns which, if any, of the mouse buttons has changed state.
int	getClickCount() Returns the number of mouse clicks associated with this event.
static String	getMouseModifiersText(int modifiers) Returns a String describing the modifier keys and mouse buttons that were down during the event, such as "Shift", or "Ctrl+Shift".
Point	getPoint() Returns the x,y position of the event relative to the source component.
int	getX() Returns the horizontal x position of the event relative to the source component.
int	getY() Returns the vertical y position of the event relative to the source component.
boolean	isPopupTrigger() Returns whether or not this mouse event is the popup menu trigger event for the platform.
String	paramString() Returns a parameter string identifying this event.
void	translatePoint(int x, int y) Translates the event's coordinates to a new position by adding specified x (horizontal) and y (vertical) offsets.

Methods inherited from class java.awt.event.InputEvent

consume, getModifiers, getModifiersEx, getModifiersExText, getWhen, isAltDown, isAltGraphDown, isConsumed, isControlDown, isMetaDown, isShiftDown

Methods inherited from class java.awt.event.ComponentEvent

getComponent

Methods inherited from class java.awt.AWTEvent

getID, toString

Methods inherited from class java.util.EventObject

getSource

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

MOUSE_FIRST

public static final int MOUSE_FIRST

The first number in the range of ids used for mouse events.

See Also:

Constant Field Values

MOUSE_LAST

public static final int MOUSE_LAST

The last number in the range of ids used for mouse events.

See Also:

Constant Field Values

MOUSE_CLICKED

public static final int MOUSE_CLICKED

The "mouse clicked" event. This MouseEvent occurs when a mouse button is pressed and released.

See Also:

Constant Field Values

MOUSE_PRESSED

public static final int MOUSE_PRESSED

The "mouse pressed" event. This MouseEvent occurs when a mouse button is pushed down.

See Also:

Constant Field Values

MOUSE_RELEASED

public static final int MOUSE_RELEASED

The "mouse released" event. This MouseEvent occurs when a mouse button is let up.

See Also:

Constant Field Values

MOUSE_MOVED

public static final int MOUSE_MOVED

The "mouse moved" event. This MouseEvent occurs when the mouse position changes.

See Also:

Constant Field Values

MOUSE_ENTERED

public static final int MOUSE_ENTERED

The "mouse entered" event. This MouseEvent occurs when the mouse cursor enters the unobscured part of component's geometry.

See Also:

Constant Field Values

MOUSE_EXITED

public static final int MOUSE_EXITED

The "mouse exited" event. This MouseEvent occurs when the mouse cursor exits the unobscured part of component's geometry.

See Also:

Constant Field Values

MOUSE_DRAGGED

public static final int MOUSE_DRAGGED

The "mouse dragged" event. This MouseEvent occurs when the mouse position changes while a mouse button is pressed.

See Also:

Constant Field Values

MOUSE_WHEEL

public static final int MOUSE_WHEEL

The "mouse wheel" event. This is the only MouseWheelEvent. It occurs when a mouse equipped with a wheel has its wheel rotated.

Since:

1.4

See Also:

Constant Field Values

NOBUTTON

public static final int NOBUTTON

Indicates no mouse buttons; used by getButton().

Since:

1.4

See Also:

Constant Field Values

BUTTON1

public static final int BUTTON1

Indicates mouse button #1; used by getButton().

Since:

1.4

See Also:

Constant Field Values

BUTTON2

public static final int BUTTON2

Indicates mouse button #2; used by getButton().

Since:

1.4

See Also:

Constant Field Values

BUTTON3

public static final int BUTTON3

Indicates mouse button #3; used by getButton().

Since:

1.4

See Also:

Constant Field Values

Constructor Detail

MouseEvent

public MouseEvent(Component source,
          int id,
          long when,
          int modifiers,
          int x,
          int y,
          int clickCount,
          boolean popupTrigger,
          int button)

Constructs a MouseEvent object with the specified source component, type, modifiers, coordinates, and click count.

Note that passing in an invalid id results in unspecified behavior.

Parameters:

source - the Component that originated the event

id - the integer that identifies the event

when - a long int that gives the time the event occurred

modifiers - the modifier keys down during event (e.g. shift, ctrl, alt, meta) Either extended _DOWN_MASK or old _MASK modifiers should be used, but both models should not be mixed in one event. Use of the extended modifiers is preferred.

x - the horizontal x coordinate for the mouse location

y - the vertical y coordinate for the mouse location

clickCount - the number of mouse clicks associated with event

popupTrigger - a boolean, true if this event is a trigger for a popup menu

button - which of the mouse buttons has changed state. NOBUTTON, BUTTON1, BUTTON2 or BUTTON3.

Throws:

IllegalArgumentException - if if an invalid button value is passed in.

Since:

1.4

MouseEvent

public MouseEvent(Component source,
          int id,
          long when,
          int modifiers,
          int x,
          int y,
          int clickCount,
          boolean popupTrigger)

Constructs a MouseEvent object with the specified source component, type, modifiers, coordinates, and click count.

Note that passing in an invalid id results in unspecified behavior.

Parameters:

source - the Component that originated the event

id - the integer that identifies the event

when - a long int that gives the time the event occurred

modifiers - the modifier keys down during event (e.g. shift, ctrl, alt, meta) Either extended _DOWN_MASK or old _MASK modifiers should be used, but both models should not be mixed in one event. Use of the extended modifiers is preferred.

x - the horizontal x coordinate for the mouse location

y - the vertical y coordinate for the mouse location

clickCount - the number of mouse clicks associated with event

popupTrigger - a boolean, true if this event is a trigger for a popup menu

Method Detail

getX

public int getX()

Returns the horizontal x position of the event relative to the source component.

Returns:

x an integer indicating horizontal position relative to the component

getY

public int getY()

Returns the vertical y position of the event relative to the source component.

Returns:

y an integer indicating vertical position relative to the component

getPoint

public Point getPoint()

Returns the x,y position of the event relative to the source component.

Returns:

a Point object containing the x and y coordinates relative to the source component

translatePoint

public void translatePoint(int x,
                  int y)

Translates the event's coordinates to a new position by adding specified x (horizontal) and y (vertical) offsets.

Parameters:

x - the horizontal x value to add to the current x coordinate position

y - the vertical y value to add to the current y coordinate position

getClickCount

public int getClickCount()

Returns the number of mouse clicks associated with this event.

Returns:

integer value for the number of clicks

getButton

public int getButton()

Returns which, if any, of the mouse buttons has changed state.

Returns:

one of the following constants: NOBUTTON, BUTTON1, BUTTON2 or BUTTON3.

Since:

1.4

isPopupTrigger

public boolean isPopupTrigger()

Returns whether or not this mouse event is the popup menu trigger event for the platform.

Note: Popup menus are triggered differently on different systems. Therefore, isPopupTrigger should be checked in both mousePressed and mouseReleased for proper cross-platform functionality.

Returns:

boolean, true if this event is the popup menu trigger for this platform

getMouseModifiersText

public static String getMouseModifiersText(int modifiers)

Returns a String describing the modifier keys and mouse buttons that were down during the event, such as "Shift", or "Ctrl+Shift". These strings can be localized by changing the awt.properties file.

Parameters:

modifiers - a modifier mask describing the modifier keys and mouse buttons that were down during the event

Returns:

string a text description of the combination of modifier keys and mouse buttons that were down during the event

Since:

1.4

paramString

public String paramString()

Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

Overrides:

paramString in class ComponentEvent

Returns:

a string identifying the event and its attributes