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/* You might want to create
areas where the user can click instead
of using buttons. Somtimes your whole
applet will have to be clickable and that is
where the MouseListener comes
in.
We are going to create an applet that
will show where the user has clicked,
that will also tell if he clicked on
a hotspot and if the mouse is in the applet
or not.
*/
import java.awt.*;
import java.applet.*;
// import an extra class for the
MouseListener
import java.awt.event.*;
// Tells the applet you will be using
the MouseListener methods.
public class MouseClickExample
extends Applet implements MouseListener
{
// The X-coordinate and
Y-coordinate of the last click.
int xpos;
int ypos;
// The coordinates of the
rectangle we will draw.
// It is easier to specify this
here so that we can later
// use it to see if the mouse
is in that area.
int
rect1xco,rect1yco,rect1width,rect1height;
// The variable that will tell
whether or not the mouse
// is in the applet
area.
boolean mouseEntered;
// variable that will be true
when the user clicked in the rectangle
// then we will draw.
boolean rect1Clicked;
public void
init()
{
// Assign values to the
rectanagle coordinates.
rect1xco = 20;
rect1yco = 20;
rect1width = 100;
rect1height = 50;
// Add the MouseListener to
your applet
addMouseListener(this);
}
public void paint(Graphics g)
{
// Rectangle's
color
g.setColor(Color.green);
g.fillRect(rect1xco,rect1yco,rect1width,rect1height);
g.setColor(Color.red);
// When the user clicks this
will show the coordinates of the click
// at the place of the
click.
g.drawString("("+xpos+","+ypos+")",xpos,ypos);
// If the click was in the
rectangle show this message
if (rect1Clicked) g.drawString("You clicked in the
Rectangle",20,120);
// else this one
else g.drawString("You clicked outside of the
rectangle",20,120);
if (mouseEntered) g.drawString("Mouse is in the applet
area",20,160);
else g.drawString("Mouse is
outside the Applet area",20,160);
}
/* These methods always have to be
present when you implement MouseListener
public void mouseClicked
(MouseEvent me) {}
public void mouseEntered
(MouseEvent me) {}
public void mousePressed
(MouseEvent me) {}
public void mouseReleased
(MouseEvent me) {}
public void mouseExited
(MouseEvent me) {}
*/
// This method will be called
when the mouse has been clicked.
public void mouseClicked
(MouseEvent me) {
// Save the coordinates of the
click like this.
xpos = me.getX();
ypos = me.getY();
// Check if the click was
inside the rectangle area.
if (xpos > rect1xco && xpos <
rect1xco+rect1width && ypos >rect1yco
&&
ypos <
rect1yco+rect1height) rect1Clicked = true;
// if it was not then
rect1Clicked is false;
else
rect1Clicked =
false;
//show the results of the
click
repaint();
}
// This is called when the mouse
has been pressed
public void mousePressed
(MouseEvent me) {}
// When it has been
released
// not that a click also calls
these Mouse-Pressed and Released.
// since they are empty nothing
happens here.
public void mouseReleased
(MouseEvent me) {}
// This is executed when the
mouse enters the applet. it will only
// be executed again when the
mouse has left and then re-entered.
public void mouseEntered (MouseEvent me) {
// Will draw the "inside
applet message"
mouseEntered = true;
repaint();
}
// When the Mouse leaves the
applet.
public void mouseExited (MouseEvent me) {
// will draw the "outside
applet message"
mouseEntered = false;
repaint();
}
/* So now you can use the
MouseListener instead of Buttons. These methods will be
ones that you will
often use. These methods are good for
mouseClicks, but when you need mouseOvers like in
Javascript
then you'll need the
MouseMotionListener.
Go to
MouseMotionExample.java
*/
}
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