/* You might want to create yourself 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 i the rectangle
// the 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 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 lke
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 mous 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 hapens
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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