Characteristics:

1. Components/Event Sources cannot be easily accessed from Listener methods. We must have object of base class(where we have components) in the Listener class(where we have Listener methods)
2. Event can be applied to a component by passing object of newly created adapter class which extends built in adapter class.
3. View and Controller part can be separated which is a good practice.
4. Not compulsory to define all the methods. No need to write Blank definition if not required.

Code:

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class EventDemo5 extends Applet
{
	Button btn;
	static Label lbl;
	public void init()
	{
		btn = new Button("Click Me!");
		lbl = new Label("          ");
		add(btn);
		add(lbl);

		myAdapterClass myObj = new myAdapterClass();
		btn.addMouseListener(myObj);		
	}		 
 }
 
 class myAdapterClass extends MouseAdapter
 {
	public void mouseClicked(MouseEvent e)
	{
	 EventDemo5.lbl.setText("Clicked!");
	} 
  }
  
/*
<applet code="EventDemo5" width="500" height="50"></applet>
*/

The post Extending Adapter Class appeared first on Ankit Virparia.

Characteristics:

1. Components/Event Sources can be easily accessed from Listener methods
2. To apply an event we have to pass anonymous object of Adapter class
3. Logic is to be written in complex inner methods
4. Not compulsory to define all the methods. No need to write Blank definition if not required.

Code:

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class EventDemo4 extends Applet
{
	Button btn;
	Label lbl;
	public void init()
	{
		btn = new Button("Click Me!");
		lbl = new Label("          ");
		add(btn);
		add(lbl);

		btn.addMouseListener(new MouseAdapter()
		{
			public void mouseClicked(MouseEvent e)
			{
				lbl.setText("Clicked");
			}
		});		
	}	
	 
 }
/*
<applet code="EventDemo4" width="500" height="50"></applet>
*/

The post Anonymous Adapter Class appeared first on Ankit Virparia.

Characteristics:

1. Components/Event Sources can be easily accessed from Listener methods
2. To apply an event we have to pass anonymous object of Listener Interface
3. Logic is to be written in complex inner methods
4. All the methods must be defined. Blank definition is to be given even if we don’t want to use it.

Code:

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class EventDemo3 extends Applet
{
	Button btn;
	Label lbl;
	public void init()
	{
		btn = new Button("Click Me!");
		lbl = new Label("          ");
		add(btn);
		add(lbl);

		btn.addMouseListener(new MouseListener()
		{
			public void mouseClicked(MouseEvent e){ lbl.setText("Clicked!"); } 
			public void mouseEntered(MouseEvent e){}
			public void mouseExited(MouseEvent e){}
			public void mousePressed(MouseEvent e){} 
			public void mouseReleased(MouseEvent e){}			
		});		
	}	
	 
 }
/*
<applet code="EventDemo3" width="500" height="50"></applet>
*/

The post Anonymous Listener Interface appeared first on Ankit Virparia.

Characteristics:

1. Components/Event Sources cannot be easily accessed from Listener methods. We must have object of base class(where we have components) in the Listener class(where we have Listener methods)
2. Event can be applied to a component by passing object of newly created Listener class.
3. View and Controller part can be separated which is a good practice.
4. All the methods must be defined in our newly created class. Blank definition is to be given even if we don’t want to use it.

Code:

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class EventDemo2 extends Applet
{
	Button btn;
	static Label lbl;
	public void init()
	{
		btn = new Button("Click Me!");
		lbl = new Label("          ");
		add(btn);
		add(lbl);
		myListenerClass myobj = new myListenerClass();
		btn.addMouseListener(myobj);
	}	
	
	
 }
 
  class myListenerClass implements MouseListener
  {
	public void mouseClicked(MouseEvent e)
	{
	 EventDemo2.lbl.setText("Clicked!");
	} 
	public void mouseEntered(MouseEvent e){}
	public void mouseExited(MouseEvent e){}
	public void mousePressed(MouseEvent e){} 
	public void mouseReleased(MouseEvent e){} 
  }
/*
<applet code="EventDemo2" width="500" height="50"></applet>
*/

The post Event Listener and Event Source in the different class appeared first on Ankit Virparia.

Characteristics:

1. Components/Event Sources can be easily accessed from Listener methods
2. Event can be applied to any component by passing current object(this). No need of creating other object.
3. View as well as Logic is combined in single class which is a bad practice.
4. All the methods must be defined. Blank definition is to be given even if we don’t want to use it.

Code:

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class EventDemo1 extends Applet implements MouseListener
{
	Button btn;
	Label lbl;
	public void init()
	{
		btn = new Button("Click Me!");
		lbl = new Label("          ");
		add(btn);
		add(lbl);
		btn.addMouseListener(this);
	}	
	public void mouseClicked(MouseEvent e)
	{
	 lbl.setText("Clicked!");
	} 
	public void mouseEntered(MouseEvent e){}
	public void mouseExited(MouseEvent e){}
	public void mousePressed(MouseEvent e){} 
	public void mouseReleased(MouseEvent e){} 
 }
/*
<applet code="EventDemo1" width="500" height="50"></applet>
*/

The post Event Listener and Event Source in the same class appeared first on Ankit Virparia.