Java The Complete Reference, Seventh Edition

646 Part II: The Java Library

The MouseEvent Class

There are eight types of mouse events. TheMouseEventclass defines the following integer

constants that can be used to identify them:

MOUSE_CLICKED The user clicked the mouse.

MOUSE_DRAGGED The user dragged the mouse.

MOUSE_ENTERED The mouse entered a component.

MOUSE_EXITED The mouse exited from a component.

MOUSE_MOVED The mouse moved.

MOUSE_PRESSED The mouse was pressed.

MOUSE_RELEASED The mouse was released.

MOUSE_WHEEL The mouse wheel was moved.

MouseEventis a subclass ofInputEvent. Here is one of its constructors:

MouseEvent(Componentsrc, inttype, longwhen, intmodifiers,

intx, inty, intclicks, booleantriggersPopup)

Here,srcis a reference to the component that generated the event. The type of the event is

specified bytype.The system time at which the mouse event occurred is passed inwhen.The

modifiersargument indicates which modifiers were pressed when a mouse event occurred.

The coordinates of the mouse are passed inxandy.The click count is passed inclicks.The

triggersPopupflag indicates if this event causes a pop-up menu to appear on this platform.

Two commonly used methods in this class aregetX( )andgetY( ). These return the X and

Y coordinates of the mouse within the component when the event occurred. Their forms are

shown here:

int getX( )

int getY( )

Alternatively, you can use thegetPoint( )method to obtain the coordinates of the mouse.

It is shown here:

Point getPoint( )

It returns aPointobject that contains the X,Y coordinates in its integer members:xandy.

ThetranslatePoint( )method changes the location of the event. Its form is shown here:

void translatePoint(intx, inty)

Here, the argumentsxandyare added to the coordinates of the event.

ThegetClickCount( )method obtains the number of mouse clicks for this event.

Its signature is shown here:

int getClickCount( )

TheisPopupTrigger( )method tests if this event causes a pop-up menu to appear on this

platform. Its form is shown here: