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M	astering Java Swing - Part 2 : Menus n' Events
	Getting Event Information: Event Objects
	Every event-listener method has a single argument -- an object that inherits from the EventObject class. Although the argument always descends from EventObject, its type is generally specified more precisely. For example, the argument for methods that handle mouse events is an instance of MouseEvent, where MouseEvent is an indirect subclass of EventObject. The EventObject class defines one very useful method: Object getSource() Returns the object that fired the event. Note that the getSource method returns an Object. Event classes sometimes define methods similar to getSource, but that have more restricted return types. For example, the ComponentEvent class defines a getComponent method that -- just like getSource -- returns the object that fired the event. The difference is that getComponent always returns a Component. Each how-to page in this lesson describes whether you should use getSource or another method to get the event source. Often, an event class defines methods that return information about the event. For example, you can query a MouseEvent object for information about where the event occurred, how many clicks the user made, which modifier keys were pressed, and so on. DOWNLOAD CODE: swing1.zip

Adding Menu Items and Calling MenuItem Events

So far i hope that u were able to run GBLayout.java successfully and now we keep a copy of this file and create a new file GBLayout.java which starts as an exact copy of GBLayout.java , we find "GBLayout" and replace with "GBLayout2" in our code .......

Now we setup a Menu named "File" -> and Menu Item Exit associated with it
and Next to file we set up a Menu named "Style" -> The has 3 menu items Windows, Motif, Metal
by default any swing has "Metal" as its default look but we can make windows and Motif too...

once the user clicks on a Menu Item we catch that Event and if its Exit item we make the application to exit, if its Metal we make the Look Metal , if its Windows we change the look to Windows Classic Look if its Motif look we change the look to Motif,

For our Menu item to load these styles we require few more imports like import javax.swing.plaf.metal.*; etc..

Motif Look and Feel

Windows Look and Feel

Metal Look and Feel

Actual Code To Build Menus and Change Look and Feel

1) Fonts in Maroon Color are Responsible for Setting up a Menu Bar and Fixing it to our Application
2) In the above Maroon Block of Code observe the Line in Bold , this shows the way Menu item Click Event is Handled
3) Fonts in Blue are Responsible for Capturing the Menu Item Click Event and Loading Corresponding Display Styles
4) Observe the Line Blue and Bold UIManager.setLookAndFeel(motifLF) which show how UIManager is Loaded
5) For our User Interface to Have many Stylish layout our import statement has been changed observe the one in Bold
6) The Lines in Red buttonF.addActionListener(new ButtonHandler()); is responsible for making the Button "ButtonF" Sensitive
7) The ButtonHandler Block in Red is Responsible to trigger an Event in case of Button Click, Observe the one in Bold and Red
8) We are not Doing any Hi Fi Event Handling Just Sending a Message in to the DOS Prompt which button is clicked

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.*;
import javax.swing.plaf.metal.*;
import com.sun.java.swing.plaf.motif.*;
import com.sun.java.swing.plaf.windows.*;

public class GBLayout2 extends JFrame
{
 JButton buttonF, buttonP, buttonN, buttonL;
 public static void main(String args[])
 {
  GBLayout2 app = new GBLayout2();
 }
 public GBLayout2() 
 {
  super("James Smith's Java"); 
  setupMenuBar();
  setup();
  pack();  					 
  show();
 }	
// Setting Up Menu Bar ---------------------------------------------------
void setupMenuBar() 
{
  MenuBar menuBar = new MenuBar();

  Menu fileMenu = new Menu("File");		
   MenuItem fileExit = new MenuItem("Exit");		
    fileExit.addActionListener(new MenuItemHandler()); 
     fileMenu.add(fileExit);					
   menuBar.add(fileMenu);

   Menu styleMenu = new Menu("Style");		
   MenuItem styleWin = new MenuItem("Windows");	
    styleWin.addActionListener(new MenuItemHandler()); 
     styleMenu.add(styleWin);
   MenuItem styleMotif = new MenuItem("Motif");
    styleMotif.addActionListener(new MenuItemHandler()); 
     styleMenu.add(styleMotif);
   MenuItem styleMetal = new MenuItem("Metal");
    styleMetal.addActionListener(new MenuItemHandler()); 	
     styleMenu.add(styleMetal);						
      menuBar.add(styleMenu);
     setMenuBar(menuBar);
}

// Handling Menu Items --------------------------------------------------
MetalLookAndFeel metalLF = new MetalLookAndFeel();
MotifLookAndFeel motifLF = new MotifLookAndFeel();
WindowsLookAndFeel windowsLF = new WindowsLookAndFeel();
class MenuItemHandler implements ActionListener 
{
 public void actionPerformed(ActionEvent ev)
 {
  String s=ev.getActionCommand();
  if(s=="Exit")
  {
   System.exit(0);
  }
  else if(s=="Windows")
  {
   try
   {
    UIManager.setLookAndFeel(windowsLF);
    SwingUtilities.updateComponentTreeUI(GBLayout2.this);
   }
   catch(Exception e)
   {
    System.out.println("Could not Load Windows Look n Feel");
   }
  }				
 else if(s=="Motif")
 {
  try
  {
   UIManager.setLookAndFeel(motifLF);
   SwingUtilities.updateComponentTreeUI(GBLayout2.this);
  }
  catch(Exception e)
  {
   System.out.println("Could not Load Motif Look n Feel");
  }
}	
else if(s=="Metal")
{
  try
  {
   UIManager.setLookAndFeel(metalLF);
   SwingUtilities.updateComponentTreeUI(GBLayout2.this);
  }
  catch(Exception e)
  {
   System.out.println("Could not Load Metal Look n Feel");
  }
 }			
}	
}
public void setup()
{
 Font dataFont = new Font("courier new",Font.PLAIN,12);
 Font titleFont = new Font("courier new",Font.BOLD,14);
 Font titleFont1 = new Font("courier new",Font.BOLD,12);

 GridBagLayout gridbag = new GridBagLayout();
 GridBagConstraints c = new GridBagConstraints();		       
 c.fill = GridBagConstraints.HORIZONTAL;

 Container contentPane = getContentPane();		
 contentPane.setLayout(gridbag);

 JPanel jpanel1 = new JPanel();		
 jpanel1 = new JPanel() 
 {
  public Dimension getPreferredSize() 
  {
   Dimension size = super.getPreferredSize();				
   size.width = 700;
   size.height = 400;
   return size;
  }
};	
 jpanel1.setBorder
 (BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(),
 "Video CD Database Application"));
 jpanel1.setLayout(gridbag);

 // Row 1 Components -------------------------------------------	    
 JLabel jlabel4 = new JLabel(" Sl No : ");
 jlabel4.setFont(titleFont1);		
 c.fill = GridBagConstraints.BOTH;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 0;       						     
 c.gridy = 0;       						
 gridbag.setConstraints(jlabel4, c);				
 jpanel1.add(jlabel4);	

 JLabel jlabel5 = new JLabel(" 12 ");
 jlabel5.setFont(dataFont);		
 c.fill = GridBagConstraints.BOTH;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 1;       						     
 c.gridy = 0;     
 gridbag.setConstraints(jlabel5, c);				
 jpanel1.add(jlabel5);

 JLabel jlabel1 = new JLabel(" Movie Database  ");
 jlabel1.setBorder
 (BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder()));
 jlabel1.setFont(titleFont);
 c.fill = GridBagConstraints.CENTER;	
 c.weightx = 0.5;				
 c.gridx = 2;       	//3rd Col  -- Very Important
 c.gridy = 0;       	//0th Row  -- Very Important
 gridbag.setConstraints(jlabel1, c);				
 jpanel1.add(jlabel1);

 // Row 2 Components -------------------------------------------	    
 JLabel jlabel2 = new JLabel(" Title : ");
 jlabel2.setFont(titleFont1);		
 c.fill = GridBagConstraints.BOTH;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 0;       						     
 c.gridy = 1;       						
 gridbag.setConstraints(jlabel2, c);				
 jpanel1.add(jlabel2);	

 JLabel jlabel3 = new JLabel(" Blonde Babes ");
 jlabel3.setFont(dataFont);		
 c.fill = GridBagConstraints.BOTH;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 1;       						     
 c.gridy = 1;       						
 gridbag.setConstraints(jlabel3, c);				
 jpanel1.add(jlabel3);	

 buttonF = new JButton(new ImageIcon("first.gif"));
  c.fill = GridBagConstraints.BOTH;
  c.ipady = 1;		
  c.ipadx = 1;
  c.gridx = 4;
  c.gridy = 1;
  c.insets = new Insets(5,0,0,0);
  buttonF.addActionListener(new ButtonHandler());
  gridbag.setConstraints(buttonF, c);
 jpanel1.add(buttonF);

 buttonP = new JButton(new ImageIcon("back.gif"));
  c.fill = GridBagConstraints.BOTH;
  c.ipady = 1;		
  c.ipadx = 1;
  c.gridx = 5;       						     
  c.gridy = 1;
  buttonP.addActionListener(new ButtonHandler());
  gridbag.setConstraints(buttonP, c);
 jpanel1.add(buttonP);

 buttonN = new JButton(new ImageIcon("next.gif"));
  c.fill = GridBagConstraints.BOTH;		
  c.ipady = 1;       						
  c.ipadx = 1;  
  c.gridx = 6;       						     
  c.gridy = 1;
  buttonN.addActionListener(new ButtonHandler()); 
  gridbag.setConstraints(buttonN, c);				
 jpanel1.add(buttonN);

 buttonL = new JButton(new ImageIcon("last.gif"));
  c.fill = GridBagConstraints.BOTH;		
  c.ipady = 1;       						
  c.ipadx = 1;  
  c.gridx = 7;       						     
  c.gridy = 1;
  buttonL.addActionListener(new ButtonHandler()); 
  gridbag.setConstraints(buttonL, c);				
 jpanel1.add(buttonL);		

 //Row 3 Components -----------------------------------------
 JLabel jlabel6 = new JLabel(" Star : ");
 jlabel6.setFont(titleFont1);		
 c.fill = GridBagConstraints.BOTH;	
 c.insets = new Insets(5,0,0,0); 	
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 0;       						     
 c.gridy = 2;       						
 gridbag.setConstraints(jlabel6, c);				
 jpanel1.add(jlabel6);	

 JLabel jlabel7 = new JLabel(" Anna Nicole ");
 jlabel7.setFont(dataFont);		
 c.fill = GridBagConstraints.BOTH;				 
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 1;       						     
 c.gridy = 2;       						
 gridbag.setConstraints(jlabel7, c);				
 jpanel1.add(jlabel7);	

 //Row 4 ---------------------------------------------------
 ButtonGroup bg = new ButtonGroup();	
 JLabel jlabel8 = new JLabel(" Ratings : ");
 jlabel8.setFont(titleFont1);		
 c.fill = GridBagConstraints.BOTH;		
 c.insets = new Insets(5,0,0,0);   
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 0;       						     
 c.gridy = 3;       						
 gridbag.setConstraints(jlabel8, c);				
 jpanel1.add(jlabel8);	

 JRadioButton radio1 = new JRadioButton("Adult Video",false);
 radio1.setFont(dataFont);		
 c.fill = GridBagConstraints.WEST;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 1;       						     
 c.gridy = 3;       						
 bg.add(radio1);
 gridbag.setConstraints(radio1, c);				
 jpanel1.add(radio1);

 JRadioButton radio2 = new JRadioButton("General Viewing",true);
 radio2.setFont(dataFont);		
 c.fill = GridBagConstraints.WEST;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 2;       						     
 c.gridy = 3;       					
 bg.add(radio2);	
 gridbag.setConstraints(radio2, c);				
 jpanel1.add(radio2);

 JRadioButton radio3 = new JRadioButton("Childrens",false);
 radio3.setFont(dataFont);		
 c.fill = GridBagConstraints.WEST;		
 c.ipady = 1;       						
 c.ipadx = 1;  
 c.gridx = 3;       						     
 c.gridy = 3; 
 bg.add(radio3);      						
 gridbag.setConstraints(radio3, c);				
 jpanel1.add(radio3);

 // Row 5 -------------------------------------------
 JLabel labelim = new JLabel(new ImageIcon("Anna.jpg"));
 labelim.setFont(dataFont);		
 c.fill = GridBagConstraints.BOTH;				
 c.ipady = 1;       						
 c.ipadx = 1;  
 labelim.setPreferredSize(new Dimension(200, 221));
 c.gridx = 2;       						     
 c.gridy = 4;       						
 gridbag.setConstraints(labelim, c);				
 jpanel1.add(labelim);

 addWindowListener(new WindowEventHandler());	
 contentPane.add(jpanel1);
}
// Handle Button Clicks First, Prev, Next , Last ----------------
class ButtonHandler implements ActionListener 
{
  public void actionPerformed(ActionEvent ev)
  {   			 
  if(ev.getSource()== buttonF) 
  {
   System.out.println("First is Clicked");			
  } 
  else if(ev.getSource()== buttonP) 
  {
   System.out.println("Prev is Clicked");			
  }
  else if(ev.getSource()== buttonN) 
  {
   System.out.println("Next is Clicked");			
  }
  else if(ev.getSource()== buttonL) 
  {
   System.out.println("Last is Clicked");			
  } 
 }
}
//Handle Window Application Exit ------------------------
class WindowEventHandler extends WindowAdapter 
{
 public void windowClosing(WindowEvent e)
 {
  System.exit(0);
 }
}	
}

What Next ? Mastering Java Swing Part 3 : Database Connectivity and Button Handling , Database Navigation.....

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