JList Sample Code                             Peter Komisar


/* Here's a sample using DefaultListModel as an argument to JList. The default list model
    encapsulates the data and provides methods for adding and removing this information to
    the view provided by the JList component. I have also included some code to line up the
    listings added to the JList. This code only works with a fixed proportion font like
  "Monospaced". In a fixed proportion font, (versus a proportional font), all letters occupy
    the same width, (whether an " i "or a " w ").  */
//_____________________________________________________________________________

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class Listing extends JFrame implements ActionListener{

//declarations

JList jl;
DefaultListModel dlm;
JTextField tf1;
JTextField tf2;
JTextField tf3;

JPanel jp;
JLabel label1;
JLabel label2;
JLabel label3;

// constructor

Listing( ){
jp=new JPanel();

jp.setLayout(new GridLayout(2,3));

tf1=new JTextField("Enter from any");
tf2=new JTextField("field, enters");
tf3=new JTextField("all fields");

tf1.addActionListener(this);
tf2.addActionListener(this);
tf3.addActionListener(this);
 

label1=new JLabel("First Name");
label2=new JLabel("Last Name");
label3=new JLabel("Phone Number");

jp.add(label1);
jp.add(label2);
jp.add(label3);

jp.add(tf1);
jp.add(tf2);
jp.add(tf3);

getContentPane().add(jp, BorderLayout.SOUTH);

dlm=new DefaultListModel( );   // here's the default list model object
jl=new JList(dlm);
jl.setFont(new Font("Monospaced",Font.BOLD,14));
jl.setBackground(new Color(215,235,255));

getContentPane().add(jl, BorderLayout.CENTER);
}

// action method

public void actionPerformed(ActionEvent ae){
String formatted=format(tf1.getText(),tf2.getText(),tf3.getText());
dlm.addElement(formatted);
}

// The following two methods take care of making all the strings the same length by adding
// an appropriate number of blank spaces

String format(String s1, String s2, String s3){
String sTotal;
int i=   18 - s1.length( );
int ii=  18 - s2.length( );
int iii= 18 - s3.length( );
sTotal=
" " + s1 + spaceMaker(i) + s2 + spaceMaker(ii) +  s3 +spaceMaker(iii);
return sTotal;
}

String spaceMaker(int x){
String space="";
for(int q=0;q<x;q++)
space=space+" ";
return space;
}

// main( )

public static void main(String[] args){
Listing l=new Listing();
l.setSize(480,300);
l.setVisible(true);
}
}