|
JSR 216 (Maintenance Release) | ||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object java.util.EventObject java.awt.AWTEvent java.awt.event.ComponentEvent java.awt.event.InputEvent java.awt.event.MouseEvent java.awt.event.MouseWheelEvent
An event which indicates that the mouse wheel was rotated in a component.
A wheel mouse is a mouse which has a wheel in place of the middle button. This wheel can be rotated towards or away from the user. Mouse wheels are most often used for scrolling, though other uses are possible.
A MouseWheelEvent object is passed to every MouseWheelListener
object which registered to receive the "interesting" mouse events using the
component's addMouseWheelListener
method. Each such listener
object gets a MouseEvent
containing the mouse event.
Due to the mouse wheel's special relationship to scrolling Components, MouseWheelEvents are delivered somewhat differently than other MouseEvents. This is because while other MouseEvents usually affect a change on the Component directly under the mouse cursor (for instance, when clicking a button), MouseWheelEvents often have an effect away from the mouse cursor.
MouseWheelEvents start delivery from the Component underneath the mouse cursor. If MouseWheelEvents are not enabled on the Component, the event is delivered to the first ancestor Container with MouseWheelEvents enabled. The source Component and x,y coordinates will be relative to the event's final destination.
Some AWT Components are implemented using native widgets which display their own scrollbars and handle their own scrolling. The particular Components for which this is true will vary from platform to platform. When the mouse wheel is moved over one of these Components, the event is delivered straight to the native widget, and not propagated to ancestors.
Platforms offer customization of the amount of scrolling that should take place when the mouse wheel is moved. The two most common settings are to scroll a certain number of "units" (commonly lines of text in a text-based component) or an entire "block" (similar to page-up/page-down). The MouseWheelEvent offers methods for conforming to the underlying platform settings. These platform settings can be changed at any time by the user. MouseWheelEvents reflect the most recent settings.
Note: The generation of mouse wheel events is not guaranteed. Applications should not be written to rely on the receipt of such events for proper operation. Nonetheless, applications may still create MouseWheelEvent objects and post them to the system event queue.
MouseWheelListener
,
Serialized FormField Summary | |
static int |
WHEEL_BLOCK_SCROLL
Constant representing scrolling by a "block" (like scrolling with page-up, page-down keys) |
static int |
WHEEL_UNIT_SCROLL
Constant representing scrolling by "units" (like scrolling with the arrow keys) |
Fields inherited from class java.awt.event.MouseEvent |
BUTTON1, BUTTON2, BUTTON3, MOUSE_CLICKED, MOUSE_DRAGGED, MOUSE_ENTERED, MOUSE_EXITED, MOUSE_FIRST, MOUSE_LAST, MOUSE_MOVED, MOUSE_PRESSED, MOUSE_RELEASED, MOUSE_WHEEL, NOBUTTON |
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.util.EventObject |
source |
Constructor Summary | |
MouseWheelEvent(Component source,
int id,
long when,
int modifiers,
int x,
int y,
int clickCount,
boolean popupTrigger,
int scrollType,
int scrollAmount,
int wheelRotation)
Constructs a MouseWheelEvent object with the
specified source component, type, modifiers, coordinates,
scroll type, scroll amount, and wheel rotation. |
Method Summary | |
int |
getScrollAmount()
Returns the number of units that should be scrolled in response to this event. |
int |
getScrollType()
Returns the type of scrolling that should take place in response to this event. |
int |
getUnitsToScroll()
This is a convenience method to aid in the implementation of the common-case MouseWheelListener. |
int |
getWheelRotation()
Returns the number of "clicks" the mouse wheel was rotated. |
String |
paramString()
Returns a parameter string identifying this event. |
Methods inherited from class java.awt.event.MouseEvent |
getButton, getClickCount, getMouseModifiersText, getPoint, getX, getY, isPopupTrigger, translatePoint |
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 |
public static final int WHEEL_UNIT_SCROLL
getScrollType()
,
Constant Field Valuespublic static final int WHEEL_BLOCK_SCROLL
getScrollType()
,
Constant Field ValuesConstructor Detail |
public MouseWheelEvent(Component source, int id, long when, int modifiers, int x, int y, int clickCount, boolean popupTrigger, int scrollType, int scrollAmount, int wheelRotation)
MouseWheelEvent
object with the
specified source component, type, modifiers, coordinates,
scroll type, scroll amount, and wheel rotation.
Note that passing in an invalid id
results in
unspecified behavior.
source
- the Component
that originated
the eventid
- the integer that identifies the eventwhen
- a long that gives the time the event occurredmodifiers
- the modifier keys down during event
(shift, ctrl, alt, meta)x
- the horizontal x coordinate for the mouse locationy
- the vertical y coordinate for the mouse locationclickCount
- the number of mouse clicks associated with eventpopupTrigger
- a boolean, true if this event is a trigger for a
popup-menuscrollType
- the type of scrolling which should take place in
response to this event; valid values are
WHEEL_UNIT_SCROLL
and
WHEEL_BLOCK_SCROLL
scrollAmount
- for scrollType WHEEL_UNIT_SCROLL
,
the number of units to be scrolledwheelRotation
- the amount that the mouse wheel was rotated (the
number of "clicks")MouseEvent.MouseEvent(java.awt.Component, int, long, int, int, int, int, boolean)
Method Detail |
public int getScrollType()
Adjustable.getUnitIncrement()
,
Adjustable.getBlockIncrement()
public int getScrollAmount()
getScrollType
returns
MouseWheelEvent.WHEEL_UNIT_SCROLL
getScrollType
returns
MouseWheelEvent.WHEEL_BLOCK_SCROLL
getScrollType()
public int getWheelRotation()
public int getUnitsToScroll()
This method returns the number of units to scroll when scroll type is
MouseWheelEvent.WHEEL_UNIT_SCROLL, and should only be called if
getScrollType
returns MouseWheelEvent.WHEEL_UNIT_SCROLL.
Direction of scroll, amount of wheel movement, and platform settings for wheel scrolling are all accounted for. This method does not and cannot take into account value of the Adjustable unit increment, as this will vary among scrolling components.
getScrollType()
,
getScrollAmount()
,
MouseWheelListener
,
Adjustable
,
public String paramString()
paramString
in class MouseEvent
|
JSR 216 (Maintenance Release) | ||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |