Unit-16 Event Handling

Java

Handling Mouse Events in Java…

Example : MouseEvents

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code="MouseEvents"width=300 height=100>
</applet>
*/
public class MouseEvents extends java.applet.Applet
implements MouseListener,MouseMotionListener
{
String msg="";
int mouseX=0,mouseY=0;
public void init()
{
addMouseListener(this);
addMouseMotionListener(this);
}
public void mouse(MouseEvent me)
{
mouseX=0;
mouseY=10;
msg="Mouse .";
repaint();
}
public void mouseClicked(MouseEvent me)
{
mouseX=0;
mouseY=10;
msg="Mouse clicked .";
repaint();
}
public void mouseEntered(MouseEvent me)
{
mouseX=0;
mouseY=10;
msg="Mouse entered .";
repaint();
}
public void mouseExited(MouseEvent me)
{
mouseX=0;
mouseY=10;
msg="Mouse exited .";
repaint();
}
public void mousePressed(MouseEvent me)
{
mouseX=0;
mouseY=10;
msg="Mouse pressed .";
repaint();
}
public void mouseReleased(MouseEvent me)
{
mouseX=me.getX();
mouseY=me.getY();
msg="Up";
repaint();
}
public void mouseDragged(MouseEvent me)
{
mouseX=me.getX();
mouseY=me.getY();
msg="*";
showStatus("Dragging mouse at"+mouseX+","+mouseY);
repaint();
}
public void  mouseMoved(MouseEvent me)
{
showStatus("Moving mouse at"+me.getX()+","+me.getY());
}
public void paint(Graphics g)
{
g.drawString(msg,mouseX,mouseY);
}
}
Output : MouseEvents

Keyboard Events in Java…

Example : SimpleKey

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code="SimpleKey"width=300 height=100>
</applet>
*/
public class SimpleKey extends java.applet.Applet
implements KeyListener
{
String msg="";
int X=10,Y=20;
public void init()
{
addKeyListener(this);
requestFocus();
}
public void keyPressed(KeyEvent ke)
{
showStatus("Key Down");
}
public void keyReleased(KeyEvent ke)
{
showStatus("Key Up");
}
public void keyTyped(KeyEvent ke)
{
msg+=ke.getKeyChar();
repaint();
}
public void paint(Graphics g)
{
g.drawString(msg,X,Y);
}
}
Output : SimpleKey

Adapter Classes in Java…

Example : MouseAdapterDemo

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
/*
<applet code="MouseAdapterDemo"width=100 height=100>
</applet>
*/
public class MouseAdapterDemo extends java.applet.Applet
{
public void init()
{
setBackground(Color.green);
addMouseListener(new MyMouseAdapter(this));
}
}
class MyMouseAdapter extends MouseAdapter
{
MouseAdapterDemo m;
public  MyMouseAdapter(MouseAdapterDemo m)
{
this.m=m;
}
public void mousePressed(MouseEvent me)
{
m.setBackground(Color.red);
m.repaint();
}
public void mouseReleased(MouseEvent me)
{
m.setBackground(Color.green);
m.repaint();
}
}
Example : MouseAdapterDemo